Disk Utility reports "resource busy" and can't create an disk image

HI,

Just succesfully updated to Mountain Lion on my MBA and iMac. No problems. A very smooth proces.

But, on my iMac the Disk Utility are not able to create new images at all! I'm not sure if this relates directly to the update, as

DU works fine on the MBA.

I have tried to create a simple disk image from a folder, sparse bundle disk images and sparse disk images - with and without encryption.

They al gave this output from DU: "Unable to create "MYDiskImage.sparsebundle." (Resource busy).

I understand from other postings on the web that others have experienced the same message from time to time, but have not seen a fix for it anywhere.

I can see the "disk iamge" in the DU window (left pane) but are not able to locate it with Finder or on the computer anywhere, but are even able to "repair the

disk image with DU, but then there is actually no disk image when trying to locate it. Very strange.

Any help?

The DU log has this info:

1. Creating a sparsebundle

2012-08-01 07:46:16 +0200: Creating Image “MyDiskImage.sparsebundle”

2012-08-01 07:46:16 +0200: Initializing…

2012-08-01 07:46:16 +0200: Creating…

2012-08-01 07:46:27 +0200: Formatting…

2012-08-01 07:46:28 +0200: Finishing…

2012-08-01 07:46:29 +0200: Unable to create “MyDiskImage.sparsebundle.” (Resource busy)

2012-08-01 07:46:29 +0200:

2012-08-01 07:47:01 +0200: Verify and Repair volume “disk3s2”

2012-08-01 07:47:01 +0200: Starting repair tool:

2012-08-01 07:47:01 +0200: Checking file system2012-08-01 07:47:01 +0200: Checking Journaled HFS Plus volume.

2. Creating a disk image from a folder

2012-08-01 07:59:10 +0200: Creating Image “Parallels køb juli 2012.dmg”

2012-08-01 07:59:10 +0200: Initializing…

2012-08-01 07:59:11 +0200: Creating…

2012-08-01 07:59:20 +0200: Finishing…

2012-08-01 07:59:21 +0200: Unable to create “Parallels køb juli 2012.” (Resource busy)

2012-08-01 07:59:21 +0200: