Vista - Vista Network JPG Thumbnail issue

Have a problem with Windows Vista Home Premium and jpg file
thumbnails.

The scenario is - I have two laptops, one running Service Pack 1, and
one running Service Pack 2.

When browsing folders on the network from the laptop with SP1, all
thumbnails are generated and displayed with no problems.

When browsing with the laptop running SP2, the thumbnails start
generating, then disappear, leaving just the default 'jpg' icon.

Have found various forum posts relating to this issue and unchecking
the archive flag of individual files then gives a thumbnail, but it
doesn't work when selecting multiple files, so is not feasible to
change each file.

Have also disabled, rebooted, enabled, rebooted the thumbnail view on
the problematic laptop.

Any ideas please?

Thanks.