Have you noticed the Office 365 directory sync database just getting larger and larger… If so try the following to clear the sync runs
1. Open the MIISClient.exe and click the Operations tab.
2. From the Actions menu, select "Clear Runs"
3. On the Clear Runs dialog
a. Uncheck the option "save runs before clearing them"
b. Click to select "Clear runs before: " radio button
c. Select a date that will clear runs starting with the oldest, not trying to clear more than about a week at a time.
IMPORTANT: This is pretty important as this operation will cause the transaction log file to grow temporarily. When trying to clear too many runs all at once, the transaction log file could grow a lot, possibly running out of disk space on the drive hosting the file.
4. Wait for it to finish the clear operation
a. This will be apparent when the list of runs has been modified to remove the runs just cleared.
5. Repeat as necessary
Written by Daniel Kenyon-Smith