I am experiencing the same symptoms, as reported by Jim.
However, the explanation, about, 'Try again', doesn't work.
If I 'Search for Updates', it tells me, 'No Updates available'
If I select another server, it prompts me to 'Select some Updates'.
I have received 'Bad Checksum', on the last 5 Updates, and this was using many of the servers available.
I have tried the manual Updater... it only Updates to what was current, a few months back.
Is there some method to 'back-out' the downloaded definition files, so I can 'Search for Updates', and it won't see that I have them ('Bad Checksum') ? Presumably, it won't let me select Updates, which it assumes I have ?
:scratch:
Love the product, it HAS worked well... but, lately, not so well...