For those using MediaWiki for their site wiki installations, we have a valuable tip that as of yet, we have not seen anybody else deal with.
You log in with a user such as Administrator that should have full admin privileges, but once logged in you are still unable to perform the extra tasks such as deleting content or removing accounts.
The issue discovered for this particular update was found that previous versions of the data found in the user_groups table in the main database were originally a fixed length. During some update for MediaWiki, the group fields were changed from a fixed length to be variable.
We discovered that our database carried the old version of group fields so that users listed as “sysops” had a field description of something like “sysops “, with a significant amount of blank space at the end of the field. Ultimately, it was causing the connection with the specific administrative groups to be incorrect, which ultimately broke the ability to perform any administrative task.
To correct, simply remove the extra space at the end of the field for each line in the user_groups table. If you have many lines, you can write a quick sql update statement to change all instances in the file.