diff --git a/release/scripts/startup/bl_ui/space_toolsystem_common.py b/release/scripts/startup/bl_ui/space_toolsystem_common.py
index cde430c1e6f..2f25de24ca8 100644
--- a/release/scripts/startup/bl_ui/space_toolsystem_common.py
+++ b/release/scripts/startup/bl_ui/space_toolsystem_common.py
@@ -480,8 +480,7 @@ class ToolSelectPanelHelper:
             kc_default.keymaps.new(km_idname, **km_kwargs)
 
     @classmethod
-    def register(cls):
-        wm = bpy.context.window_manager
+    def _register_defer(cls, wm):
         # Write into defaults, users may modify in preferences.
         kc_default = wm.keyconfigs.default
 
@@ -510,6 +509,23 @@ class ToolSelectPanelHelper:
                 if callable(keymap_data[0]):
                     cls._km_action_simple(kc_default, kc_default, context_descr, item.label, keymap_data)
 
+    @classmethod
+    def register(cls):
+        try:
+            wm = bpy.context.window_manager
+        except:
+            # Delay registering tools until we have a window manager.
+            @bpy.app.handlers.persistent
+            def fn(_x, _y):
+                wm = bpy.context.window_manager
+                cls._register_defer(wm)
+                bpy.app.handlers.load_post.remove(fn)
+
+            bpy.app.handlers.load_post.append(fn)
+            return
+
+        cls._register_defer(wm)
+
     @classmethod
     def keymap_ui_hierarchy(cls, context_mode):
         # See: bpy_extras.keyconfig_utils
diff --git a/source/blender/windowmanager/intern/wm_files.c b/source/blender/windowmanager/intern/wm_files.c
index abf957a6396..0a26395aced 100644
--- a/source/blender/windowmanager/intern/wm_files.c
+++ b/source/blender/windowmanager/intern/wm_files.c
@@ -673,6 +673,7 @@ static void wm_file_read_post(bContext *C,
   if (use_data) {
     /* important to do before NULL'ing the context */
     BKE_callback_exec_null(bmain, BKE_CB_EVT_VERSION_UPDATE);
+    printf("Running post\n");
     BKE_callback_exec_null(bmain, BKE_CB_EVT_LOAD_POST);
     if (is_factory_startup) {
       BKE_callback_exec_null(bmain, BKE_CB_EVT_LOAD_FACTORY_STARTUP_POST);
diff --git a/source/blender/windowmanager/intern/wm_init_exit.c b/source/blender/windowmanager/intern/wm_init_exit.c
index d7ea47fc625..c3d26f5e06d 100644
--- a/source/blender/windowmanager/intern/wm_init_exit.c
+++ b/source/blender/windowmanager/intern/wm_init_exit.c
@@ -290,16 +290,6 @@ void WM_init(bContext *C, int argc, const char **argv)
 
   BLI_assert((G.fileflags & G_FILE_NO_UI) == 0);
 
-  wm_homefile_read(C,
-                   NULL,
-                   G.factory_startup,
-                   false,
-                   use_data,
-                   use_userdef,
-                   NULL,
-                   WM_init_state_app_template_get(),
-                   &is_factory_startup);
-
   /* Call again to set from userpreferences... */
   BLT_lang_set(NULL);
 
@@ -320,22 +310,12 @@ void WM_init(bContext *C, int argc, const char **argv)
     if (!WM_platform_support_perform_checks()) {
       exit(-1);
     }
-
-    UI_init();
   }
 
   BKE_subdiv_init();
 
   ED_spacemacros_init();
 
-  /* NOTE(campbell): there is a bug where python needs initializing before loading the
-   * startup.blend because it may contain PyDrivers. It also needs to be after
-   * initializing space types and other internal data.
-   *
-   * However can't redo this at the moment. Solution is to load python
-   * before wm_homefile_read() or make py-drivers check if python is running.
-   * Will try fix when the crash can be repeated. */
-
 #ifdef WITH_PYTHON
   BPY_python_start(C, argc, argv);
   BPY_python_reset(C);
@@ -366,8 +346,6 @@ void WM_init(bContext *C, int argc, const char **argv)
   }
 #endif
 
-  BLI_strncpy(G.lib, BKE_main_blendfile_path_from_global(), sizeof(G.lib));
-
 #ifdef WITH_COMPOSITOR
   if (1) {
     extern void *COM_linker_hack;
@@ -375,29 +353,21 @@ void WM_init(bContext *C, int argc, const char **argv)
   }
 #endif
 
-  {
-    Main *bmain = CTX_data_main(C);
-    /* NOTE: logic here is from wm_file_read_post,
-     * call functions that depend on Python being initialized. */
-
-    /* normally 'wm_homefile_read' will do this,
-     * however python is not initialized when called from this function.
-     *
-     * unlikely any handlers are set but its possible,
-     * note that recovering the last session does its own callbacks. */
-    CTX_wm_window_set(C, CTX_wm_manager(C)->windows.first);
-
-    BKE_callback_exec_null(bmain, BKE_CB_EVT_VERSION_UPDATE);
-    BKE_callback_exec_null(bmain, BKE_CB_EVT_LOAD_POST);
-    if (is_factory_startup) {
-      BKE_callback_exec_null(bmain, BKE_CB_EVT_LOAD_FACTORY_STARTUP_POST);
-    }
+  wm_homefile_read(C,
+                   NULL,
+                   G.factory_startup,
+                   false,
+                   use_data,
+                   use_userdef,
+                   NULL,
+                   WM_init_state_app_template_get(),
+                   &is_factory_startup);
 
-    wm_file_read_report(C, bmain);
+  BLI_strncpy(G.lib, BKE_main_blendfile_path_from_global(), sizeof(G.lib));
 
-    if (!G.background) {
-      CTX_wm_window_set(C, NULL);
-    }
+  if (!G.background) {
+    /* Reads theme settings. */
+    UI_init();
   }
 }