I was receiving an error "Processing WLLDATA1 Error: Unfreeze error: [Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. A VSS critical writer has failed. Writer name: [SqlServerWriter]. " So, I applied Cumulative Update package 2 for SQL Server 2012 SP2 on to my vM DR & Data Server. I'm thinking I wasn't suppose to apply the patch on to the DR vm server, but on the backup and replication pc, because although the backup finally ran to completion on Fri and Saturday night, it also blocked all access to the D: drive on the VM Server. I was getting E:\ is not accessible. Access Denied. I was up with Dell Support until 5am this morning. He eventually, copied the drive to another Server and we were able to open it, but when we moved it back to our Data Server, we got the same message. So we renamed the old drive letter to E: and copied the old drive to a newly created D: drive and was able to access the data on the D; drive. However, the newly E: drive is with is still configured on Disk1 in Disk Management is still inaccessible. Any idea's ?