How do I disable UserAssist on Windows 10?

Question

My team runs a performance lab where we run continuous integration tests of our software on Windows 10. We noticed that explorer.exe occasionally starts to use a full core's worth of CPU for long periods of time. By using Process Monitor, I found that explorer.exe was frequently accessing a specific registry key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\{CEBFF5CD-ACE2-4F4F-9178-9926F41749EA}.

This registry key apparently helps UserAssist maintain "a list of applications, files, links, and other objects that have been accessed" (source).

When I open the UserAssist\CEBFF5CD-... key in regedit and click on the "Count" subfield, regedit freezes.

When I delete the entire UserAssist\CEBFF5CD-... key, I immediately see explorer.exe's CPU usage drop from a full core to <1%.

I want to disable UserAssist to prevent it from interfering with performance tests, but am having trouble doing so. So far I've tried:

• This website's suggestion of creating a UserAssist\Settings key with a DWORD value named NoLog under it with value 1, then restarting explorer.exe.
• This website's suggestion to disable both "Privacy" options when under the start menu settings. (I had to alter these instructions slightly for Windows 10.) I also restarted explorer.exe after this.

I continued to see accesses to this registry key and high CPU use of explorer.exe after each of these attempted fixes.

How can I disable UserAssist on Windows 10 to stop UserAssist from affecting my performance tests?

Answer 1

To answer my own question: after getting in touch with Microsoft, here's what worked.

Disabling UserAssist requires two steps:

1. Set two registry keys, HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_TrackProgs and HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Start_TrackEnabled, both to zero in order to signal that we want UserAssist disabled.

2. Clear your registry subtrees that look like HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\<hash>.

Answer 2

Navigate to HKEY_Current_User\Software\Microsoft\Windows\Currentvers ion\Explorer\Userassist. You should see two subkeys called Count, delete both these keys. Now right-click the UserAssist key and create a new key named Settings. In this key create a DWORD value named NoLog, set the value to 1.

Answer 3

I found this question while trying to turn UserAssist on for my PC. In the General section of the Privacy settings, disabling "Let Windows track app launches to improve Start and search results" had disabled UserAssist tracking for me. Enabling it turned UserAssist back on.