CatError.log file is 24GB. How to shrink it?

You have to stop Backup Exec services in order to delete or rename the CatError.log file.

So your recommended course of action would be:

1. Stop Backup Exec services via Backup Exec console - Configuration and Settings - Backup Exec Services.
2. Delete or rename the CatError.log file.
3. Start Backup Exec services again. This will create a new CatError.log file, initially empty.
4. Watch the CatError.log file to see whether it starts growing again.
5. If it does, open a support call.

You may also have a peek at its content while it is still small enough to open.

by any chance, is this a CAS-MMS setup with distrubuted catalogs?

If it is... thn this is a known issue and is currently under investigations as per the following technote:

http://www.symantec.com/docs/TECH204760

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It looks like, but i not really famillilar with abraviation CASO (Central Administration Server Option) and MMS (Managed Media Server).

I have one Central Administration Server on my environement.

It's killing my space and sometimes backup and restore really slow.

Thansk pkh, I seen this post.

I guess my only option is open a support case