Figured out the problem. The issue was no thumbnails in the Admin/Skins and Host/Skins. Our web servers are on a NLB cluster, our databases are on a serve cluster and the websites folders are on A share located on another computer. In this case a network share on the server cluster. When we moved the website to a local drive the thumbnails reappeared under Admin/Skins and Host/Skins. There was some issue with the file manage and css files that were associated with the skins. If the files in the folder did not match the file mapping in the database and Synchronize was run, "Object not set to the reference of an object" error would appear.  But all seemed to have been resolved when the we moved the website to a local drive on the web servers.

I do not know if this is a recognized problem with working with server farms (NLB and cluster) and shared file servers.

The problem began around the time we moved our sites from a single server to new servers running under the NLB and server cluster. We have six dnn sites. Most of the sites have been online for a least 2 years.

At first we thought it had something to do with their location.

Example:

So I moved one of the site to a rootlevel.

Still had the same issue.

Side note: We recently upgraded the sites to 3.3.7. Did notice that only one of the six site actually brought up the upgrade screen, the others went straight to the portal.

So I moved one site to a local drive it has been running without a hitch since.

It's making the boss nervous, after spending $$$$ on the new servers to provide redundancy.

I am open to suggestions though. We really would like these sites to work using a shared file location.

Thank you for your time.

Richard