I used to encounter this frequently, but it seems to have been a few years now. Not sure what changed. Anyway, the fastest way to deal with it was to long-press the R key. This activated Retry multiple times per second and seemed to be the best way to find out when the 'underlying service' (whatever that was!) was ready to let the software continue opening.
this happens to me continuously if Ive got my auto backup running and its scanning my PS files, Ive changed it to only backup at the end of the day now.
