This behavior matches known issues where volumes or disks go offline or appear with invalid mount points, which then prevents Shadow Copies and backup tools from correctly enumerating them.
Use the following steps to verify and correct the disk/volume state before configuring Shadow Copies again:
- Confirm the volume is online with DiskPart
- Open an elevated Command Prompt.
- Run:
diskpart list volume - Identify the volume that corresponds to the D: drive.
- If it shows as offline, bring it online:
select volume <N> online volume - Exit DiskPart.
- Verify the partition table and file system
- Open Disk Management (
diskmgmt.msc). - Check that the disk and the D: partition are shown as Healthy and that the file system is NTFS.
- If the volume ever appears as RAW or unformatted, or if there are partition boundary issues, use either:
- Disk Management (right‑click the disk/volume and inspect properties), or
-
diskpartagain to review the partition layout (list disk,select disk,list partition).
chkdsk /fon the D: volume to repair NTFS issues before retrying Shadow Copies. - Open Disk Management (
- Check for cluster or mount‑point issues (if applicable)
If this server is part of a cluster and the disk is a cluster disk, verify in Failover Cluster Manager that:
- The disk resource is online.
- There are no messages such as “Cluster Disk X contains an invalid mount point.”
- Reconfigure Shadow Copies after the volume is healthy and online
Once the D: volume is confirmed online, healthy, and correctly mounted:
- Open Computer Management → Disk Management.
- Right‑click the D: drive → Properties → Shadow Copies tab.
- Configure Shadow Copies, ensuring the storage area is on a volume that is online and has sufficient free space.
vssadmin:vssadmin list shadowstorage /for=D: vssadmin resize shadowstorage /for=D: /on=D: /maxsize=<NewSize>mb - If issues persist
- If the disk repeatedly goes offline or volumes intermittently appear as RAW or missing, follow the iSCSI/storage troubleshooting guidance to check for controller or disk issues, verify partition tables, and run vendor diagnostics.
- If necessary, attach the disk to a later Windows Server version or another system to validate the volume and recover data.
These steps ensure the D: volume is online, correctly mounted, and healthy so that Shadow Copies and backup agents can enumerate and use it.
References:
- System Partition goes offline after installing some third-party disk or Storage Management Software
- iSCSI storage connectivity troubleshooting guidance
- Shadow copies are deleted on Windows Server when you try to run an FCI classification job
- The source disk is still offline when you disable the shadow copy schedule for the disk in Windows