Error Code 14:200: Description: UpdateIndex failed on MediaAgent - Index files are missing.
Article ID: DAPR0012 Non-Full backup job fails when attempting to update index on MediaAgent
Backup job goes pending during backup phase when attempting to update index on MediaAgent
MediaAgent performing backup does not have access to index cache holding the index. Most likely configuration/cause is the index cache is on another MediaAgent (due to failover/load balancing) or a network share and the job experienced network loss or interruption.
Other possible cause is insufficient index cache space.
Verify the Index Cache volume has sufficient space. Recommend a minimum of 500MB free disk space be available. Actual needed free disk space will vary depending on size of index. See BOL for recommended Index Cache disk space.
If network interruption, verify connectivity between data mover MediaAgent and MediaAgent holding the index. Usually this means all MediaAgent paths available in the Storage Policy Primary copy.