Thinstall tries to determine which registry keys a COM control will use by:
Step 1. Thinstall tells the control to unregister itself from your (the developer) system registry. The control should delete all registry keys it placed in your registry it might have placed there previously.
Step 2. Thinstall tells the control to register itself on your (the developer) system registry. The control should create all registry keys it needs during this process. Thinstall records all registry keys created.
Step 3. After the control has registered itself in Step 2 and all the keys it has created have been created, Thinstall will generate a text .threg file from this.
The problem: Some controls do not properly delete all registry keys they use in Step 1, so recording in Step 2 may miss these keys.
The solution: If you have a troublesome COM control, you may try manually searching your registry and deleting all traces of this control. After you have done this record a new registry script. If this fails you may need to try recording the registry script on a fresh version of Windows.