External drive self unmounting

**MaCiNToSHeR** · 05-10-2009

Hello friends. I have a problem with my portable external USB hard disk [320GB]. I use this drive to take time machine backup. The thing is, whenever i connect my external usb drive for time machine backup, after some time it disappears. External drive self unmounting if no activity is done with the disk. Any help?

**ApplePowerPC** · 05-10-2009

Hey, thanks for posting this topic. I have this problem with my disk too. My disk is a USB powered External Disk [500Gigs] which has one usb for data and other for power. I don't know what is causing this. But if there is no activity done on the disk, it dismounts automatically. Is there a setting which i need to disable? Please help pals...

**Solomon** · 05-10-2009

Do you have any custom applescript installed? I think there is this script or any software which may be checking for activity on these disk and dismounts it when no activity is done. Do you have any third part disk softwares installed? May be that is doing this too.

Well otherwise normally this is not possible!

**Rudra.J** · 05-10-2009

Try to run disk utility check on these drives. Open disk utility and select your USB drive. Click on Verify and repair. Does this give you any problem? See if the repair is successful, does the self dismounting happens? Also check if there are not errors which are not fixed by disk utility, if this happens, backup your disk and repartition it. That would fix your problem...