diff --git a/src/App/Application.cpp b/src/App/Application.cpp
index fe2b62ebf2..1486a0463a 100644
--- a/src/App/Application.cpp
+++ b/src/App/Application.cpp
@@ -34,6 +34,7 @@
 #  define WINVER 0x502 // needed for SetDllDirectory
 #  include <Windows.h>
 # endif
+# include <boost/algorithm/string.hpp>
 # include <boost/program_options.hpp>
 # include <boost/date_time/posix_time/posix_time.hpp>
 # include <boost/scope_exit.hpp>
@@ -1339,18 +1340,15 @@ void Application::changeImportModule(const char* filter, const char* oldModuleNa
     }
 }
 
-std::vector<std::string> Application::getImportModules(const char* extension) const
+std::vector<std::string> Application::getImportModules(const std::string& extension) const
 {
     std::vector<std::string> modules;
     for (const auto & it : _mImportTypes) {
         const std::vector<std::string>& types = it.types;
         for (const auto & jt : types) {
-#ifdef __GNUC__
-            if (strcasecmp(extension, jt.c_str()) == 0)
-#else
-            if (_stricmp(extension, jt.c_str()) == 0)
-#endif
+            if (boost::iequals(extension, jt)) {
                 modules.push_back(it.module);
+            }
         }
     }
 
@@ -1369,16 +1367,13 @@ std::vector<std::string> Application::getImportModules() const
     return modules;
 }
 
-std::vector<std::string> Application::getImportTypes(const char* Module) const
+std::vector<std::string> Application::getImportTypes(const std::string& Module) const
 {
     std::vector<std::string> types;
     for (const auto & it : _mImportTypes) {
-#ifdef __GNUC__
-        if (strcasecmp(Module,it.module.c_str()) == 0)
-#else
-        if (_stricmp(Module,it.module.c_str()) == 0)
-#endif
+        if (boost::iequals(Module, it.module)) {
             types.insert(types.end(), it.types.begin(), it.types.end());
+        }
     }
 
     return types;
@@ -1397,18 +1392,15 @@ std::vector<std::string> Application::getImportTypes() const
     return types;
 }
 
-std::map<std::string, std::string> Application::getImportFilters(const char* extension) const
+std::map<std::string, std::string> Application::getImportFilters(const std::string& extension) const
 {
     std::map<std::string, std::string> moduleFilter;
     for (const auto & it : _mImportTypes) {
         const std::vector<std::string>& types = it.types;
         for (const auto & jt : types) {
-#ifdef __GNUC__
-            if (strcasecmp(extension,jt.c_str()) == 0)
-#else
-            if (_stricmp(extension,jt.c_str()) == 0)
-#endif
+            if (boost::iequals(extension, jt)) {
                 moduleFilter[it.filter] = it.module;
+            }
         }
     }
 
@@ -1464,18 +1456,15 @@ void Application::changeExportModule(const char* filter, const char* oldModuleNa
     }
 }
 
-std::vector<std::string> Application::getExportModules(const char* extension) const
+std::vector<std::string> Application::getExportModules(const std::string& extension) const
 {
     std::vector<std::string> modules;
     for (const auto & it : _mExportTypes) {
         const std::vector<std::string>& types = it.types;
         for (const auto & jt : types) {
-#ifdef __GNUC__
-            if (strcasecmp(extension,jt.c_str()) == 0)
-#else
-            if (_stricmp(extension,jt.c_str()) == 0)
-#endif
+            if (boost::iequals(extension, jt)) {
                 modules.push_back(it.module);
+            }
         }
     }
 
@@ -1494,16 +1483,13 @@ std::vector<std::string> Application::getExportModules() const
     return modules;
 }
 
-std::vector<std::string> Application::getExportTypes(const char* Module) const
+std::vector<std::string> Application::getExportTypes(const std::string& Module) const
 {
     std::vector<std::string> types;
     for (const auto & it : _mExportTypes) {
-#ifdef __GNUC__
-        if (strcasecmp(Module,it.module.c_str()) == 0)
-#else
-        if (_stricmp(Module,it.module.c_str()) == 0)
-#endif
+        if (boost::iequals(Module, it.module)) {
             types.insert(types.end(), it.types.begin(), it.types.end());
+        }
     }
 
     return types;
@@ -1522,18 +1508,15 @@ std::vector<std::string> Application::getExportTypes() const
     return types;
 }
 
-std::map<std::string, std::string> Application::getExportFilters(const char* extension) const
+std::map<std::string, std::string> Application::getExportFilters(const std::string& extension) const
 {
     std::map<std::string, std::string> moduleFilter;
     for (const auto & it : _mExportTypes) {
         const std::vector<std::string>& types = it.types;
         for (const auto & jt : types) {
-#ifdef __GNUC__
-            if (strcasecmp(extension,jt.c_str()) == 0)
-#else
-            if (_stricmp(extension,jt.c_str()) == 0)
-#endif
+            if (boost::iequals(extension, jt)) {
                 moduleFilter[it.filter] = it.module;
+            }
         }
     }
 
@@ -2847,8 +2830,7 @@ std::list<std::string> Application::processFiles(const std::list<std::string>& f
                 }
             }
             else {
-                std::string ext = file.extension();
-                std::vector<std::string> mods = GetApplication().getImportModules(ext.c_str());
+                std::vector<std::string> mods = GetApplication().getImportModules(file.extension());
                 if (!mods.empty()) {
                     std::string escapedstr = Base::Tools::escapedUnicodeFromUtf8(file.filePath().c_str());
                     escapedstr = Base::Tools::escapeEncodeFilename(escapedstr);
@@ -2905,9 +2887,8 @@ void Application::processCmdLineFiles()
         output = Base::Tools::escapeEncodeFilename(output);
 
         const Base::FileInfo fi(output);
-        const std::string ext = fi.extension();
         try {
-            const std::vector<std::string> mods = GetApplication().getExportModules(ext.c_str());
+            const std::vector<std::string> mods = GetApplication().getExportModules(fi.extension());
             if (!mods.empty()) {
                 Base::Interpreter().loadModule(mods.front().c_str());
                 Base::Interpreter().runStringArg("import %s",mods.front().c_str());
@@ -3702,24 +3683,23 @@ void Application::getVerboseCommonInfo(QTextStream& str, const std::map<std::str
 #endif
     str << "xerces-c " << fcXercescVersion << ", ";
 
-    const char* cmd = "import ifcopenshell\n"
-                  "version = ifcopenshell.version";
-    PyObject * ifcopenshellVer = nullptr;
-
     try {
-        ifcopenshellVer = Base::Interpreter().getValue(cmd, "version");
-    }
-    catch (const Base::Exception& e) {
-        Base::Console().log("%s (safe to ignore, unless using the BIM workbench and IFC).\n", e.what());
-    }
-
-    if (ifcopenshellVer) {
-        const char* ifcopenshellVerAsStr = PyUnicode_AsUTF8(ifcopenshellVer);
-
-        if (ifcopenshellVerAsStr) {
-            str << "IfcOpenShell " << ifcopenshellVerAsStr << ", ";
+        Base::PyGILStateLocker lock;
+        Py::Module module(PyImport_ImportModule("ifcopenshell"), true);
+        if (!module.isNull() && module.hasAttr("version")) {
+            Py::String version(module.getAttr("version"));
+            auto ver_str = static_cast<std::string>(version);
+            str << "IfcOpenShell " << ver_str.c_str() << ", ";
         }
-        Py_DECREF(ifcopenshellVer);
+        else {
+            Base::Console().log("Module 'ifcopenshell' not found (safe to ignore, unless using "
+                                "the BIM workbench and IFC).\n");
+        }
+    }
+    catch (const Py::Exception&) {
+        Base::PyGILStateLocker lock;
+        Base::PyException e;
+        Base::Console().log("%s\n", e.what());
     }
 
 #if defined(HAVE_OCC_VERSION)
diff --git a/src/App/Application.h b/src/App/Application.h
index 68331e12cf..38d7adb39e 100644
--- a/src/App/Application.h
+++ b/src/App/Application.h
@@ -561,7 +561,7 @@ public:
      *
      * @param[in] extension The file type extension.
      */
-    std::vector<std::string> getImportModules(const char* extension) const;
+    std::vector<std::string> getImportModules(const std::string& extension) const;
 
     /// Get a list of all import modules.
     std::vector<std::string> getImportModules() const;
@@ -572,7 +572,7 @@ public:
      * @param[in] Module The module name.
      * @return A list of file types (extensions) supported by the module.
      */
-    std::vector<std::string> getImportTypes(const char* Module) const;
+    std::vector<std::string> getImportTypes(const std::string& Module) const;
 
     /// Get a list of all import filetypes represented as extensions.
     std::vector<std::string> getImportTypes() const;
@@ -583,7 +583,7 @@ public:
      * @param[in] extension The file type represented by its extension.
      * @return A map of filter description to module name.
      */
-    std::map<std::string, std::string> getImportFilters(const char* extension) const;
+    std::map<std::string, std::string> getImportFilters(const std::string& extension) const;
 
     /// Get a mapping of all import filters to their modules.
     std::map<std::string, std::string> getImportFilters() const;
@@ -605,7 +605,7 @@ public:
      *
      * @copydetails getImportModules
      */
-    std::vector<std::string> getExportModules(const char* extension) const;
+    std::vector<std::string> getExportModules(const std::string& extension) const;
 
     /// Get a list of all export modules.
     std::vector<std::string> getExportModules() const;
@@ -613,9 +613,9 @@ public:
     /**
      * @brief Get a list of filetypes that are supported by a module for export.
      *
-     * @copydetails App::Application::getImportTypes(const char*) const
+     * @copydetails App::Application::getImportTypes(const std::string&) const
      */
-    std::vector<std::string> getExportTypes(const char* Module) const;
+    std::vector<std::string> getExportTypes(const std::string& Module) const;
 
     /// Get a list of all export filetypes.
     std::vector<std::string> getExportTypes() const;
@@ -623,9 +623,9 @@ public:
     /**
      * @brief Get the export filters with modules of a given filetype.
      *
-     * @copydetails App::Application::getImportFilters(const char*) const
+     * @copydetails App::Application::getImportFilters(const std::string&) const
      */
-    std::map<std::string, std::string> getExportFilters(const char* extension) const;
+    std::map<std::string, std::string> getExportFilters(const std::string& extension) const;
 
     /// Get a mapping of all export filters to their modules.
     std::map<std::string, std::string> getExportFilters() const;
diff --git a/src/App/ApplicationPy.cpp b/src/App/ApplicationPy.cpp
index 406b88a745..c1315679ae 100644
--- a/src/App/ApplicationPy.cpp
+++ b/src/App/ApplicationPy.cpp
@@ -760,7 +760,7 @@ PyObject* Application::sGetExportType(PyObject* /*self*/, PyObject* args)
         Py::Dict dict;
         std::vector<std::string> types = GetApplication().getExportTypes();
         for (const auto& it : types) {
-            std::vector<std::string> modules = GetApplication().getExportModules(it.c_str());
+            std::vector<std::string> modules = GetApplication().getExportModules(it);
             if (modules.empty()) {
                 dict.setItem(it.c_str(), Py::None());
             }
diff --git a/src/App/Expression.cpp b/src/App/Expression.cpp
index d87d381dae..1afb5ec56e 100644
--- a/src/App/Expression.cpp
+++ b/src/App/Expression.cpp
@@ -41,6 +41,7 @@
 #include <sstream>
 #include <stack>
 #include <string>
+#include <fmt/format.h>
 
 #include <App/Application.h>
 #include <App/DocumentObject.h>
@@ -3786,14 +3787,17 @@ Expression * App::ExpressionParser::parse(const App::DocumentObject *owner, cons
     // run the parser
     int result = ExpressionParser::ExpressionParser_yyparse ();
 
-    if (result != 0)
-        throw ParserError("Failed to parse expression.");
+    if (result != 0) {
+        throw ParserError(fmt::format("Failed to parse expression '{}'", buffer));
+    }
 
-    if (!ScanResult)
-        throw ParserError("Unknown error in expression");
+    if (!ScanResult) {
+        throw ParserError(fmt::format("Unknown error in expression '{}'", buffer));
+    }
 
-    if (valueExpression)
+    if (valueExpression) {
         return ScanResult;
+    }
     else {
         delete ScanResult;
         throw Expression::Exception("Expression can not evaluate to a value.");
diff --git a/src/App/PreCompiled.h b/src/App/PreCompiled.h
index 8b32f51627..973723687d 100644
--- a/src/App/PreCompiled.h
+++ b/src/App/PreCompiled.h
@@ -50,6 +50,7 @@
 #include <sstream>
 
 // STL
+#include <array>
 #include <bitset>
 #include <chrono>
 #if defined(FC_OS_WIN32)
diff --git a/src/App/ProjectFile.cpp b/src/App/ProjectFile.cpp
index 38cc61f582..bf6ec236d9 100644
--- a/src/App/ProjectFile.cpp
+++ b/src/App/ProjectFile.cpp
@@ -243,6 +243,9 @@ bool ProjectFile::loadDocument()
         try {
             Base::StdInputSource inputSource(*str, stdFile.c_str());
             parser->parse(inputSource);
+            if (parser->getErrorCount() > 0) {
+                return false;
+            }
             xmlDocument = parser->adoptDocument();
             return true;
         }
diff --git a/src/App/Property.cpp b/src/App/Property.cpp
index 491e060b35..a00a6e6ab9 100644
--- a/src/App/Property.cpp
+++ b/src/App/Property.cpp
@@ -23,6 +23,8 @@
  ***************************************************************************/
 
 #include <cassert>
+#include <array>
+#include <tuple>
 
 #include <atomic>
 #include <Base/Tools.h>
@@ -114,36 +116,35 @@ std::string Property::getFileName(const char* postfix, const char* prefix) const
     return ss.str();
 }
 
+// clang-format off
+static constexpr auto mapProps = std::to_array<std::tuple<Property::Status, PropertyType>>({
+    {App::Property::PropReadOnly,    Prop_ReadOnly},
+    {App::Property::PropHidden,      Prop_Hidden},
+    {App::Property::PropOutput,      Prop_Output},
+    {App::Property::PropTransient,   Prop_Transient},
+    {App::Property::PropNoRecompute, Prop_NoRecompute},
+    {App::Property::PropNoPersist,   Prop_NoPersist}
+});
+// clang-format on
+
 short Property::getType() const
 {
     short type = 0;
-#define GET_PTYPE(_name)                                                                           \
-    do {                                                                                           \
-        if (testStatus(App::Property::Prop##_name))                                                \
-            type |= Prop_##_name;                                                                  \
-    } while (0)
-    GET_PTYPE(ReadOnly);
-    GET_PTYPE(Hidden);
-    GET_PTYPE(Output);
-    GET_PTYPE(Transient);
-    GET_PTYPE(NoRecompute);
-    GET_PTYPE(NoPersist);
+    for (const auto& [propertyStatus, propertyType] : mapProps) {
+        if (testStatus(propertyStatus)) {
+            type |= propertyType;
+        }
+    }
     return type;
 }
 
 void Property::syncType(unsigned type)
 {
-#define SYNC_PTYPE(_name)                                                                          \
-    do {                                                                                           \
-        if (type & Prop_##_name)                                                                   \
-            StatusBits.set((size_t)Prop##_name);                                                   \
-    } while (0)
-    SYNC_PTYPE(ReadOnly);
-    SYNC_PTYPE(Transient);
-    SYNC_PTYPE(Hidden);
-    SYNC_PTYPE(Output);
-    SYNC_PTYPE(NoRecompute);
-    SYNC_PTYPE(NoPersist);
+    for (const auto& [propertyStatus, propertyType] : mapProps) {
+        if (type & propertyType) {
+            StatusBits.set((size_t)propertyStatus);
+        }
+    }
 }
 
 const char* Property::getGroup() const
diff --git a/src/App/PropertyExpressionEngine.cpp b/src/App/PropertyExpressionEngine.cpp
index 241a93ead7..c0fa969562 100644
--- a/src/App/PropertyExpressionEngine.cpp
+++ b/src/App/PropertyExpressionEngine.cpp
@@ -467,21 +467,36 @@ void PropertyExpressionEngine::afterRestore()
         ObjectIdentifier::DocumentMapper mapper(this->_DocMap);
 
         for (auto& info : *restoredExpressions) {
-            ObjectIdentifier path = ObjectIdentifier::parse(docObj, info.path);
-            if (!info.expr.empty()) {
-                std::shared_ptr<Expression> expression(
-                    Expression::parse(docObj, info.expr.c_str()));
-                if (expression) {
-                    expression->comment = std::move(info.comment);
-                }
-                setValue(path, expression);
-            }
+            tryRestoreExpression(docObj, info);
         }
         signaller.tryInvoke();
     }
     restoredExpressions.reset();
 }
 
+void PropertyExpressionEngine::tryRestoreExpression(DocumentObject* docObj,
+                                                    const RestoredExpression& info)
+{
+    try {
+        ObjectIdentifier path = ObjectIdentifier::parse(docObj, info.path);
+        if (!info.expr.empty()) {
+            std::shared_ptr<Expression> expression(
+                Expression::parse(docObj, info.expr));
+            if (expression) {
+                expression->comment = info.comment;
+            }
+            setValue(path, expression);
+        }
+    }
+    catch (const Base::Exception& e) {
+        FC_ERR("Failed to restore " << docObj->getFullName()
+                                    << '.'
+                                    << getName()
+                                    << ": "
+                                    << e.what());
+    }
+}
+
 void PropertyExpressionEngine::onContainerRestored()
 {
     Base::FlagToggler<bool> flag(restoring);
diff --git a/src/App/PropertyExpressionEngine.h b/src/App/PropertyExpressionEngine.h
index b1d83e0a56..6322892347 100644
--- a/src/App/PropertyExpressionEngine.h
+++ b/src/App/PropertyExpressionEngine.h
@@ -244,6 +244,8 @@ private:
      * into the actual map */
     std::unique_ptr<std::vector<RestoredExpression>> restoredExpressions;
 
+    void tryRestoreExpression(DocumentObject* docObj, const RestoredExpression& info);
+
     struct Private;
     std::unique_ptr<Private> pimpl;
 
diff --git a/src/App/PropertyLinks.cpp b/src/App/PropertyLinks.cpp
index 3d090cc384..f7d65a4187 100644
--- a/src/App/PropertyLinks.cpp
+++ b/src/App/PropertyLinks.cpp
@@ -4281,14 +4281,12 @@ void PropertyXLink::Restore(Base::XMLReader& reader)
         name = reader.getAttribute<const char*>("name");
     }
 
-    assert(getContainer()->isDerivedFrom<App::DocumentObject>());
     DocumentObject* object = nullptr;
     if (!name.empty() && file.empty()) {
-        DocumentObject* parent = static_cast<DocumentObject*>(getContainer());
-        Document* document = parent->getDocument();
-        object = document ? document->getObject(name.c_str()) : nullptr;
-        if (!object) {
-            if (reader.isVerbose()) {
+        if (auto parent = freecad_cast<DocumentObject*>(getContainer())) {
+            Document* document = parent->getDocument();
+            object = document ? document->getObject(name.c_str()) : nullptr;
+            if (!object && reader.isVerbose()) {
                 FC_WARN("Lost link to '" << name
                                          << "' while loading, maybe "
                                             "an object was not loaded correctly");
diff --git a/src/App/PropertyStandard.cpp b/src/App/PropertyStandard.cpp
index 57f70d9886..7530e0fd8e 100644
--- a/src/App/PropertyStandard.cpp
+++ b/src/App/PropertyStandard.cpp
@@ -3194,6 +3194,7 @@ const Base::Color& PropertyMaterialList::getDiffuseColor(int index) const
 std::vector<Base::Color> PropertyMaterialList::getDiffuseColors() const
 {
     std::vector<Base::Color> list;
+    list.reserve(_lValueList.size());
     for (auto& material : _lValueList) {
         list.push_back(material.diffuseColor);
     }
@@ -3244,6 +3245,7 @@ float PropertyMaterialList::getTransparency(int index) const
 std::vector<float> PropertyMaterialList::getTransparencies() const
 {
     std::vector<float> list;
+    list.reserve(_lValueList.size());
     for (auto& material : _lValueList) {
         list.push_back(material.transparency);
     }
diff --git a/src/App/Transactions.cpp b/src/App/Transactions.cpp
index a15a2789ac..c840b3e76a 100644
--- a/src/App/Transactions.cpp
+++ b/src/App/Transactions.cpp
@@ -147,18 +147,15 @@ void Transaction::changeProperty(TransactionalObject* Obj,
     auto& index = _Objects.get<1>();
     auto pos = index.find(Obj);
 
-    TransactionObject* To;
-
     if (pos != index.end()) {
-        To = pos->second;
+        auto To = pos->second;
+        changeFunc(To);
     }
-    else {
-        To = TransactionFactory::instance().createTransaction(Obj->getTypeId());
+    else if (auto To = TransactionFactory::instance().createTransaction(Obj->getTypeId())) {
         To->status = TransactionObject::Chn;
         index.emplace(Obj, To);
+        changeFunc(To);
     }
-
-    changeFunc(To);
 }
 
 void Transaction::renameProperty(TransactionalObject* Obj, const Property* pcProp, const char* oldName)
@@ -230,8 +227,7 @@ void Transaction::addObjectNew(TransactionalObject* Obj)
             seq.relocate(seq.end(), _Objects.project<0>(pos));
         }
     }
-    else {
-        TransactionObject* To = TransactionFactory::instance().createTransaction(Obj->getTypeId());
+    else if (auto To = TransactionFactory::instance().createTransaction(Obj->getTypeId())) {
         To->status = TransactionObject::New;
         To->_NameInDocument = Obj->detachFromDocument();
         index.emplace(Obj, To);
@@ -252,8 +248,7 @@ void Transaction::addObjectDel(const TransactionalObject* Obj)
     else if (pos != index.end() && pos->second->status == TransactionObject::Chn) {
         pos->second->status = TransactionObject::Del;
     }
-    else {
-        TransactionObject* To = TransactionFactory::instance().createTransaction(Obj->getTypeId());
+    else if (auto To = TransactionFactory::instance().createTransaction(Obj->getTypeId())) {
         To->status = TransactionObject::Del;
         index.emplace(Obj, To);
     }
@@ -264,18 +259,15 @@ void Transaction::addObjectChange(const TransactionalObject* Obj, const Property
     auto& index = _Objects.get<1>();
     auto pos = index.find(Obj);
 
-    TransactionObject* To;
-
     if (pos != index.end()) {
-        To = pos->second;
+        auto To = pos->second;
+        To->setProperty(Prop);
     }
-    else {
-        To = TransactionFactory::instance().createTransaction(Obj->getTypeId());
+    else if (auto To = TransactionFactory::instance().createTransaction(Obj->getTypeId())) {
         To->status = TransactionObject::Chn;
         index.emplace(Obj, To);
+        To->setProperty(Prop);
     }
-
-    To->setProperty(Prop);
 }
 
 
@@ -556,13 +548,12 @@ void TransactionFactory::addProducer(const Base::Type& type, Base::AbstractProdu
  */
 TransactionObject* TransactionFactory::createTransaction(const Base::Type& type) const
 {
-    std::map<Base::Type, Base::AbstractProducer*>::const_iterator it;
-    for (it = producers.begin(); it != producers.end(); ++it) {
-        if (type.isDerivedFrom(it->first)) {
-            return static_cast<TransactionObject*>(it->second->Produce());
+    for (const auto& it : producers) {
+        if (type.isDerivedFrom(it.first)) {
+            return static_cast<TransactionObject*>(it.second->Produce());
         }
     }
 
-    assert(0);
+    Base::Console().log("Cannot create transaction object from %s\n", type.getName());
     return nullptr;
 }
diff --git a/src/Gui/FileDialog.cpp b/src/Gui/FileDialog.cpp
index 58c3cf725c..40b8065c05 100644
--- a/src/Gui/FileDialog.cpp
+++ b/src/Gui/FileDialog.cpp
@@ -1098,12 +1098,12 @@ SelectModule::Dict SelectModule::exportHandler(const QStringList& fileNames, con
         QFileInfo fi(fileName);
         QString ext = fi.completeSuffix().toLower();
         std::map<std::string, std::string> filters = App::GetApplication().getExportFilters(
-            ext.toLatin1()
+            ext.toStdString()
         );
 
         if (filters.empty()) {
             ext = fi.suffix().toLower();
-            filters = App::GetApplication().getExportFilters(ext.toLatin1());
+            filters = App::GetApplication().getExportFilters(ext.toStdString());
         }
 
         fileExtension[ext].push_back(fileName);
@@ -1168,12 +1168,12 @@ SelectModule::Dict SelectModule::importHandler(const QStringList& fileNames, con
         QFileInfo fi(fileName);
         QString ext = fi.completeSuffix().toLower();
         std::map<std::string, std::string> filters = App::GetApplication().getImportFilters(
-            ext.toLatin1()
+            ext.toStdString()
         );
 
         if (filters.empty()) {
             ext = fi.suffix().toLower();
-            filters = App::GetApplication().getImportFilters(ext.toLatin1());
+            filters = App::GetApplication().getImportFilters(ext.toStdString());
         }
 
         fileExtension[ext].push_back(fileName);
diff --git a/src/Gui/MainWindow.cpp b/src/Gui/MainWindow.cpp
index 70f5d207d5..0bb8e02ddf 100644
--- a/src/Gui/MainWindow.cpp
+++ b/src/Gui/MainWindow.cpp
@@ -2453,10 +2453,10 @@ void MainWindow::loadUrls(App::Document* doc, const QList<QUrl>& urls)
                 info.setFile(info.symLinkTarget());
             }
             std::vector<std::string> module = App::GetApplication().getImportModules(
-                info.completeSuffix().toLatin1()
+                info.completeSuffix().toStdString()
             );
             if (module.empty()) {
-                module = App::GetApplication().getImportModules(info.suffix().toLatin1());
+                module = App::GetApplication().getImportModules(info.suffix().toStdString());
             }
             if (!module.empty()) {
                 // ok, we support files with this extension