OK, solved it. This will (hopefully!) be my final post on the matter! Turns out I didn't have enough disk space...the spam folder was about 700MB and I had about 500MB. Freeing up a few gigs allowed the compression to complete successfully (I guess a new PMM file needs to be created before the older one is deleted, perhaps?)

Anyway, hope this is useful to someone. David, I don't know how feasible it is to catch the reason for compression failure but if it would be possible to display something about a lack of disk space that would be helpful (assuming that was indeed the problem).

Cheers! 

Can anyone assist with the following? After deleting several thousand emails from a spam folder (which still contains many thousand more) I left clicked on my new mail folder which brought up a dialogue box stating that folder compression was taking place (which I believe is normal after deleting a large number of mails). However, after the compression notification closed I got an error message stating that an error had occurred but no mail had been lost. Either leaving this message for a few minutes or clicking OK to get rid of it triggered a folder consistency check which then led to another compression attempt which then led to the error message and...you get the picture, a loop which I couldn't break out of. Eventually I had to kill Pegasus but unfortunately on start up I get exactly the same loop once again straight away (and I can't use Pegasus any more). Many thanks in advance for any suggestions!

Edit: I've just remembered there was one extra step, I downloaded new mail just after I'd highlighted the new mail folder but while the initial compression or consistency check was underway. When I restart I can see from the message totals in the new mail folder that those new mails are accounted for but I have no access to the new mail or any other folder because of this loop.

It looks as though a number of my CNM files are corrupted, currently adding them back one at a time [:'(]

Well, I soon realised that it would actually be quicker to view each of the CNM files in a text editor and discard those which were spam before trying the remaining files! That got rid of most of them and none of those which were left appear to have been corrupted...

However, on starting up (which I could now do OK) as soon as I download new mail I get the same loop. I wonder if what's happening is that mail which is tagged as spam is being filtered to my spam folder and it's that folder which is corrupt (in some fashion) rather than the new mail itself. Any thoughts appreciated.

 

Hmm, I created a new spam folder and pointed my filter to it instead then replaced the CNM files into my mail directory (I'd removed them to allow Pegasus to start up without looping) but I still get the consistency check loop when these new files are processed. I don't see any reason why any of these new mail files should be corrupt (neither Pegasus nor any other app was doing anything when they were downloading). Is there any way to tell which folder's consistency is being checked and why? Thanks.

For anyone following this (or perhaps more likely anyone who finds it later if searching for help with a similar problem) I appear to have been able to restore normal functionality by turning folder compression off completely (set the size to zero in the appropriate options box). Somewhat surprisingly I was able to run a manual consistency check of the large spam folder and it returned no errors - I had thought there might be corruption. I guess the problem lies with the compression of the folder after deleting the large number of messages yesterday. I'm backing up now before turning compression back on to see what happens.

Turning compression back on and downloading new mail worked fine, no loop. However, manually attempting to recover deleted space from the spam folder (by right clicking and choosing the relevant option) resulted in a return to the loop once again.

So, is there any other way to recover deleted space from this folder or am I just going to have to leave compression off (and if so does that mean I can never recover deleted space)?