Cannot mount Recovery Points with Windows Deduplication enabled (4034294)

When protecting a machine that has Windows Deduplication enabled, you will receive a warning stating, "The volume which you are trying to protect has Windows deduplication on, which may cause issues with accessing the data."

When mounting a recovery point from the machine that has Windows Data Deduplication enabled, it may fail with the following error. Stack trace example:

Replay.Common.Contracts.VirtualDiskDriver.Exceptions.DeduplicationIsNotSupportedException: Deduplication is enabled for volume(s) 'X:\'. Mount operation cannot be performed because of one of the following:
• The current OS does not support deduplication
• The deduplication is enabled on source with Windows Server 2012 R2 and current environment is using Windows Server 2012

As there are several causes for this issue there are several solutions as well:

Solution 1 - Data Duplication has not been enabled on the core server:

1. If the core server operating system is 2012 or higher, add the Data Duplication role using the Add Roles and Features Wizard.
2. Adding Data Deduplication role will require a reboot of the server. Be sure to stop the core service before rebooting
3. After reboot you will be able to mount the recovery point on the core server.
4. Look out for service Data Dedeuplication Service from Windows Service Manager ( this needs to be enabled and services started)

Please Note: Windows Server 2012 does support Data Duplication, but it can only restore from other Windows Server 2012 machines with Data Deduplication enabled.

https://docs.microsoft.com/en-us/windows-server/storage/data-deduplication/install-enable

Core operating system is Windows Server 2012 or operating system does not support Data Deduplication:

Solution 2a - Use LMU on Agent machine

1. Install the Local Mount Utility (LMU) on a machine with Data Deduplication enabled.
2. Run the LMU, connect to the core, and mount the recovery point needed.
3. Restore data needed, dismount the recovery point, and close the LMU.

Solution 2b - Rebuild core operating system

1. Rebuild the core operating system to an OS that supports Windows Data Deduplication for operating systems in your environment.
2. Most recent supported operating is always recommended.
3. In place upgrades are possible, but not recommended.

Please Note: If your core is a DL Appliance you may not upgrade or rebuild your operating system. All appliances must keep the original operating system they shipped with.