diff --git a/app/main.c b/app/main.c
index 7a408d4733..deb63e833f 100644
--- a/app/main.c
+++ b/app/main.c
@@ -595,6 +595,15 @@ main (int    argc,
   gimp_init_signal_handlers (&backtrace_file);
 
 #ifdef G_OS_WIN32
+  /* Make Inno aware of gimp process avoiding broken install/unninstall */
+  char    *utf8_name = g_strdup_printf ("GIMP-%s", GIMP_MUTEX_VERSION);
+  wchar_t *name      = g_utf8_to_utf16 (utf8_name, -1, NULL, NULL, NULL);
+  
+  CreateMutexW (NULL, FALSE, name);
+  
+  g_free (utf8_name);
+  g_free (name);
+  
   /* Enable Anti-Aliasing*/
   g_setenv ("PANGOCAIRO_BACKEND", "fc", TRUE);
 
diff --git a/build/windows/installer/base_gimp3264.iss b/build/windows/installer/base_gimp3264.iss
index c4554b164a..f2a496709c 100644
--- a/build/windows/installer/base_gimp3264.iss
+++ b/build/windows/installer/base_gimp3264.iss
@@ -129,7 +129,9 @@ NotRecognizedMessagesWarning=no
 
 
 ;3.2.1 INNO INTERNAL VERSIONING (used to rule how different versions are installed)
-;Inno installer identifier: https://github.com/jrsoftware/issrc/pull/461
+;GIMP process identifier for Inno
+AppMutex=GIMP-{#GIMP_MUTEX_VERSION}
+;Inno installer identifier
 SetupMutex=GIMP-{#GIMP_MUTEX_VERSION}
 ;Inno installer (default) install location
 DefaultDirName={autopf}\GIMP {#GIMP_MUTEX_VERSION}
diff --git a/meson.build b/meson.build
index c91e8fc97d..5a4cf56149 100644
--- a/meson.build
+++ b/meson.build
@@ -103,6 +103,13 @@ endif
 # GIMP_IS_GIT can only be set during development of a RC.
 conf.set('GIMP_IS_RC_GIT', gimp_rc_git ? 1 : false)
 
+# Mutex version
+if gimp_unstable != false
+  conf.set_quoted('GIMP_MUTEX_VERSION', gimp_app_version)
+else
+  conf.set_quoted('GIMP_MUTEX_VERSION', gimp_app_version_major.to_string())
+endif
+
 versionconfig = configuration_data()
 versionconfig.set('GIMP_FULL_NAME',     full_name)
 versionconfig.set('GIMP_MAJOR_VERSION', gimp_app_version_major)