I spent a few minutes searching for a solution on the Internet, and found the following FAQ. The behavior I encountered is definitely an OE bug: it's only supposed to ask the user to compact folders after being closed 100 times. The count isn't zeroed after the first time, which makes OE ask every time it's closed, even if the folders have been compacted.
The workaround is to reset the counter to zero in the registry:
- run regedit
- navigate to
- edit the key "Compact Check Count" and set its value to zero.
I should probably automate this...