I would check these registry entries to see if anything looks out of the ordinary, and correct those items. I would highly recommend backing up the registry before making any changes per this article here:
If you aren't able to determine what entry is causing the issue, or do not feel comfortable making changes to the registry, I would recommend reaching out to Alteryx Support directly before deleting any items.
>> for me - in 'Computer\HKEY_CURRENT_USER\Software\SRC\Alteryx\10.0\MRU' one of the 'FileXX' entries (denoting paths to recent workflows) was completely blank (this was obviously out of pattern with the other keys in folder, ignoring keys '(default)' and 'max'). I deleted this key (the blank 'FileXX' key) and the issue was resolved.
As Jake notes, your IT department may not like you doing this yourself (or have disabled your ability to do it).