I briefly went through the posts on the forum, didn’t find similar issue reported, so here it is.
One of my project that I had been working on all of a sudden disappeared from the list under Active Program drop down menu, after I restarted Mbed Studio. Presumably because Mbed Studio crashed when I was trying to flash an incorrectly linked bin file.
When I checked the following folder:
That project i still listed as there.
In the end, I was able to just recreate another project with the same name, and then copy all files back.
It would be nice if there is a more direct way to recover list of projects.