Collect a client trace on the affected client. perform a VC sync and then search for the following:
HDR: ~MetaDataCacheImplStore::MetaDataCacheImplStore
HDR: FailedMetaDataCacheImpl::FailedMetaDataCacheImpl
HDR: Loading corrupt MDC for archive: 129762208998E0342B35111ED790A4AE41110000evsite.exmail.company.com
HDR: MDC file ok, but bad config. for archive: 129762208998E0342B35111ED790A4AE41110000evsite.exmail.company.com
A corrupt instance of VC may be responsible for this behavior.
VC is made of an MDC file and a series of .db files which can be found in the user profile, these can be renamed to PST so the information can be retrieved.
1. Go to C:\Users\userprofile\AppData\Local\KVS\Enterprise
2. Rename the .db files in the user profile to .pst to retrieve the messages that had been placed into VV prior to partial reset
3. Once the data has been retrieved it can be moved back to the mailbox and the files renamed back to .db
4. Perform a full Vault Cache reset which should restore VC and VV functionality
5. The messages can then be moved back into VV and a VC sync be performed which should then archive the messages.