Internal Error: Failed to expand shell folder constant "userappdata"

Hello everyone,

Thanks in advance for looking into this for me.  I get the subject message when attempting to install any most any application on my computer.  I have tried troubleshooting steps outlined in other threads to reset folder permissions on the AppData folder corresponding to the affected user profile, they have not worked :(

Are there any registry subkeys I can locate and perhaps modify/remove to correct this issue? 

I have attempted to contact tech support for various software vendors and they either tell me it's a general Windows error and unrelated to their software or they give me the troubleshooting steps to reassign folder permissions.  Neither of these solutions are helping me out here.

I am familiar with navigating and modifying the Windows registry in general, but this one has me stumped.  I understand the implications and consequences of improperly modifying the Windows registry, and do create backups prior to conducting any modifications.  I am just trying to save myself from having to format this system, which I really do not want to do.

Any help would be greatly appreciated!


Question Info

Last updated June 29, 2019 Views 65,643 Applies to:
Hi Spallina,

Thanks for visiting the Microsoft Vista Answers forum.

The only "solution" that has come anywhere near helping anyone is the following for the related Error 1606. Follow these steps to change your registry settings: (Of course, you should back up the registry before making any changes)

Click on “Start-Run, type “regedit” (without the quotes)
Navigate to this registry path:
HKEY_CURRENT_USER --> Software --> Microsoft --> Windows --> Current Version --> Explorer --> User Shell Folders
Clear the key: Recent (right mouse click on the key/folder, choose “Delete”)
Close the Registry Editor and restart the computer.

If this fails to correct your problem, the question is - how long has this been a problem?  If it has just recently surfaced, you might try a System Restore to a point in time before the problem started. Here are the steps:


The System Restore tool

If the issue that you are experiencing started occurring recently, you can use the System Restore tool. By using this tool, you can restore the computer to an earlier point in time. Using the System Restore tool may not necessarily help you determine the issue. When you use System Restore to restore the computer to a previous state, programs and updates that you installed are removed.


To restore the operating system to an earlier point in time, follow these steps:

1.     Click Start, type system restore in the Start Search box, and then click System Restore in the Programs list. If you are prompted for an administrator password or confirmation, type your password or click Continue.

2.     In the System Restore dialog box, click Choose a different restore point, and then click Next.

3.     In the list of restore points, click a restore point that was created before you began to experience the issue, and then click Next.

4.     Click Finish.

The computer restarts, and the system files and settings are returned to the state that they were in at the time that the restore point was created.

Let us know how this works and if you need more help.

Dave D
Microsoft Answers Support Engineer
Visit our Microsoft Answers Feedback Forum and let us know what you think.
Dave D

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