Thunderbird error: folder "inbox" cannot be compacted because writing to the folder failed. Verify that you have enough diskspace, or have write privileges.
I am also having random write to sent and drafts folders. they are NOT consistent, and do not appear to be related directly to the above error. And seem to occur only after about 9pm. The compact folder message ONLY occurs on the non-IMAP account folders. I have an IMAP account and compact folders works fine.
The non-IMAP folders are stored on a different drive than the default c: drive. And yes, I DO have permission to write to that drive.
ప్రత్యుత్తరాలన్నీ (1)
Issues.
If it is time based, perhaps look at what is shcheduled to occur on your computer then. Like a backup, or a sync to google drive or other events that might see contention for files like a virus scan.
Otherwise you might have a failing hard disk. Run chkdsk or other utility for your version of Windows to scan the disk for physical errors. Hard disk do not last forever and as you appear to be using windows 7 it is likely your drive is getting old by such standards.