Cisco UCCX upgrade - An error has occured but no messages are available. This can happen when another administrator is working on the system at the same time and triggers an error.

While recently working on upgrading a client from CUCM, IMP, CUC and UCCX version 9 to 11.5.X (and we'll throw Expressway in there too) I ran into a snag while upgrading UCCX.

I was diligent with preparation and found their 9.0.2.11001-24 / SU1 version did not support a direct upgrade to 11.5.1.  My plan was then to get them to 9.0.2.11003-44 / SU3 first and then to 11.5.1, a supported upgrade path.

To get to  SU3 I had Prime Collaboration Deployment install it's own ciscocm.ucmap_platformconfig.cop file during discovery, install the ciscouccx.refresh_upgrade_v1.11.cop to get it out of the way, and then turned it loose on upgrading to SU3.  That went fine although the jury is till out on what efficiency gains I made using PCD.

Shortly after triggering the upgrade to 11.5.1 I was greeted with a "Task paused due to task action failures." email from PCD.   Downloading and digging through the install logs returned nothing very obvious.  

I showed the current version to confirm I had some SU3 success and all looked good.

admin:show version active
Active Master Version: 9.0.2.11003-44
Active Version Installed Software Options:
ciscouccx.refresh_upgrade_v1.11.cop
ciscocm.ucmap_platformconfig.cop
admin:

A manual upgrade attempt made a symptom perfectly clear though.

admin:utils system upgrade initiate

Warning: Do not close this window without first canceling the upgrade.

An error has occured but no messages are available.  This can happen when another administrator is working on the system at the same time and triggers an error.

There was no other administrator with access to the system.  In the event PCD was being considered an administrator I cancelled and deleted the associated task there.  Another manual run attempt resulted in the same An error has occured but no messages are available. message though.

Google matches consistently referred to a missing refressh cop file.  All documentation indicated my ciscouccx.refresh_upgrade_v1.11.cop was appropriate, PCD indicated it completed the task for me and I could see it in the active partition myself.

Ultimately the fix was to manually install the ciscouccx.refresh_upgrade_v1.11.cop again.

Possible problem scenarios are:

1. the cop file first install used a fragged version or blew up the version of the cop file on the PCD server
2. PCD shouldn't have been used to simply install the cop file
3. the fact the cop file was installed before the upgrade to 9.0.2 SU3 rather than 11.5 invalidated its usefulness
4. stuff happen  

It seems the consensus is correct that the error points to some missing refresh upgrade preparation, but thought my "Trust me... just try it again" theory might help someone shave an hour or two off you upgrade weekend.

Good luck.