I have a 2010 workflow developed in SPD 2013. Suddenly, it does not appear in the list of workflows. The .xoml files (etc) are all still there and it still executes properly but doesn't show in the SPD 2013 list of workflows to edit. I tried restoring a previous version and it restored properly but also not visible in the workflow list. I have a copy of the same workflow on a duplicate list - I used Metavis to copy it back to the original - but it still does not appear on the workflow list for the original list.
Thoughts? - thanks in advance. (I've cleared the SPD cache several times - still no joy ) .