Running Exchange 5.5 on NT4 Server. Online defrag does not run on the private message store. I have extended the IS maintenance window but all I get is events 179 & 180 on c:\exchsrvr\DSADATA\dir.edb. There is no 1221 event stating how much free space is available.The private message store is on a logical drive d: if this makes a difference. Any advice most welcome. Ian