I'm assuming this is probably going to be a support call, but I thought I'd give it a try here first. If nothing else than to document for some other poor soul who gets caught up in this mess. Sit back and grab some popcorn. The short version is still pretty long.
We were beginning a database migration to new servers with new a new schema when the TLS security patch came out, so we decided to migrate to 10.3 first, then work on upgrading to the newest version with the new schema to give us time to make sure we didn't break anything.
Migrating our raster imagery was a complete mess. We had a lot of fits and starting over (NOTE: Do not edit your mosaic datasets in ArcGIS Pro if your users are still on ArcMap 10.3), and everything is finally in place and working except for one mosaic dataset.
I am at a loss as to what to try next.
You said "In the existing mosaic dataset
Can you try creating a new RMD with all the imagery except for the problematic image?
Can you try creating a new RMD just with the problematic image? If this works then try adding a few more images, just as a test, and see if the RMD still works?
Have you tried copying the existing RMD to the new server and just try a repair on the RMD to correct the paths (if the paths even need to be corrected as the new server setup may be identical to the old server setup)?
OK. I have a solution. I went back to the original CDs and copied the original over. It works. Now to load the 19 other directories and see what I have to re-copy, unless someone else has a better idea.
And just when I think I'm going to have to slog my way through 56 CDs trying to identify where the individual files are that I need to copy, copying from the old server to the new server works. Now generating 5 of 279 overview images.
Thanks for your help Michael Volz