The problem arises after installing KB5026372 (the May 2023 Patch Tuesday update), released on May 9, 2023. The issue affects all Windows 11 client versions (21H2 and 22H2) as well as systems running Windows Server 2022. According to Microsoft, the issue occurs only when users try to check for Effective Access permissions for shared files and folders. For those unaware, Effective Access allows you to view the effective permissions for a user, group, or device account. If the account is a member of a domain, you can also evaluate the impact of potential additions to the security token for the account. When you evaluate the impact of adding a group, any group that the intended group is a member of must be added separately. The problem described on the official Windows 11 Release Health webpage reads as follows: “After installing updates released on May 9, 2023 or later updates, you might be unable to view Effective Access in the “Advanced Security Settings” dialog for shared files or folders. On affected devices, when the “View effective access” button is selected, you will receive the message “Computing effective access….” but the results of the query might not be displayed and explorer.exe might continue to use CPU after the Advanced Security settings dialog is closed.” Thankfully, the bug is unlikely to affect regular users using Windows 11 PCs in their homes. Microsoft says customers affected by the issue can mitigate the higher-than-usual CPU usage issue by restarting their device or by signing out for the affected user. It also noted that locking Windows will not mitigate this issue; the user needs to sign out. Microsoft is already working on a resolution to fix the bug and plans to make the solution available by the end of June 2023.
