diff --git a/build-aux/windows/QElectroTech.wxs b/build-aux/windows/QElectroTech.wxs
index 7b0d97a18..00614b98f 100644
--- a/build-aux/windows/QElectroTech.wxs
+++ b/build-aux/windows/QElectroTech.wxs
@@ -97,8 +97,13 @@
         <RegistryValue Root="HKCR" Key="QElectroTech.Document" Type="string" Value="QElectroTech Project" />
         <RegistryValue Root="HKCR" Key="QElectroTech.Document\DefaultIcon" Type="string"
                        Value="[INSTALLDIR]ico\qelectrotech.ico" />
+        <!-- Pass the same arguments as the shortcuts above: opening a .qet from
+             Explorer sets the working directory to the document's folder, so a
+             bare command line leaves QET unable to locate its data. Without the
+             lang-dir argument the UI falls back to the source language, which
+             is French. See issue #554. -->
         <RegistryValue Root="HKCR" Key="QElectroTech.Document\shell\open\command" Type="string"
-                       Value="&quot;[INSTALLDIR]bin\qelectrotech.exe&quot; &quot;%1&quot;" />
+                       Value="&quot;[INSTALLDIR]bin\qelectrotech.exe&quot; --common-elements-dir=&quot;[INSTALLDIR]elements/&quot; --common-tbt-dir=&quot;[INSTALLDIR]titleblocks/&quot; --lang-dir=&quot;[INSTALLDIR]lang/&quot; $(var.QtPlatformArgs) &quot;%1&quot;" />
       </Component>
     </ComponentGroup>
 
diff --git a/cmake/paths_compilation_installation.cmake b/cmake/paths_compilation_installation.cmake
index 33fbc29d5..f8cf763dd 100644
--- a/cmake/paths_compilation_installation.cmake
+++ b/cmake/paths_compilation_installation.cmake
@@ -58,7 +58,10 @@ if(WIN32)
   set(QET_BINARY_PATH             "./")
   set(QET_COMMON_COLLECTION_PATH  "elements/")
   set(QET_COMMON_TBT_PATH         "titleblocks/")
-  set(QET_LANG_PATH               "l10n/")
+  # "lang/" and not "l10n/": that is where every Windows packaging actually
+  # puts the .qm files (see build-aux/windows/QElectroTech.wxs and the
+  # windows-build workflow), and what the shortcuts pass as --lang-dir.
+  set(QET_LANG_PATH               "lang/")
   set(QET_LICENSE_PATH            "./")
   # Liste des ressources Windows
 #RC_FILE = qelectrotech.rc
diff --git a/sources/qetapp.cpp b/sources/qetapp.cpp
index adac51c54..191e820fa 100644
--- a/sources/qetapp.cpp
+++ b/sources/qetapp.cpp
@@ -539,6 +539,48 @@ TitleBlockTemplatesCollection *QETApp::titleBlockTemplatesCollection(
 	return(nullptr);
 }
 
+/**
+	@brief resolveConfiguredDataPath
+	Resolve a data directory baked in at compile time.
+
+	An absolute path is returned unchanged. A relative one used to be
+	interpreted against the process working directory, which is only correct
+	when QET is started from its own installation folder: opening a document
+	from a file manager sets the working directory to the document's folder,
+	so the data was not found there. Resolve it against the executable
+	instead, trying the folder next to the binary and then its parent -- some
+	packagings put the binary in a "bin" subfolder with the data beside it
+	(see issue #86).
+
+	The working-directory interpretation is still attempted first, so any
+	setup that relied on it keeps working.
+
+	\~French Resout un dossier de donnees fixe a la compilation.
+	@param configured : the compile-time path
+	@return an existing directory if one is found, @a configured otherwise
+*/
+static QString resolveConfiguredDataPath(const QString &configured)
+{
+	if (configured.isEmpty() || QDir::isAbsolutePath(configured)) {
+		return(configured);
+	}
+	if (QDir(configured).exists()) {
+		return(configured);
+	}
+
+	const QString bin_dir = QCoreApplication::applicationDirPath();
+	const QStringList candidates = {
+		QDir::cleanPath(bin_dir + "/" + configured) + "/",
+		QDir::cleanPath(bin_dir + "/../" + configured) + "/"
+	};
+	for (const QString &candidate : candidates) {
+		if (QDir(candidate).exists()) {
+			return(candidate);
+		}
+	}
+	return(configured);
+}
+
 /**
 	@brief QETApp::commonElementsDir
 	@return the dir path of the common elements collection.
@@ -586,7 +628,8 @@ QString QETApp::commonElementsDir()
 		/* the compilation option represents a classic absolute
 		 *  or relative path
 		 */
-		m_common_element_dir = QUOTE(QET_COMMON_COLLECTION_PATH);
+		m_common_element_dir =
+				resolveConfiguredDataPath(QUOTE(QET_COMMON_COLLECTION_PATH));
 		return m_common_element_dir;
 #else
 		/* the compilation option represents a path
@@ -754,7 +797,7 @@ QString QETApp::commonTitleBlockTemplatesDir()
 	#ifndef QET_COMMON_COLLECTION_PATH_RELATIVE_TO_BINARY_PATH
 		// the compile-time option represents a usual path
 		// (be it absolute or relative)
-		return(QUOTE(QET_COMMON_TBT_PATH));
+		return(resolveConfiguredDataPath(QUOTE(QET_COMMON_TBT_PATH)));
 	#else
 		/* the compile-time option represents a path relative
 		 * to the directory that contains the executable binary
@@ -1261,7 +1304,7 @@ QString QETApp::languagesPath()
 		 * l'option de compilation represente
 		 *  un chemin absolu ou relatif classique
 		 */
-		return(QUOTE(QET_LANG_PATH));
+		return(resolveConfiguredDataPath(QUOTE(QET_LANG_PATH)));
 	#else
 		/* the compilation option represents a path relative
 		 *  to the folder containing the executable binary