Hyper-V incremental backups before RCT got introduced used a veritas method (standard processing method) to keep a track of changes on Hyper V virtual machine and to be able to perform Incremental or differential backup of it. The method can still be used with current BE versions when RCT is disabled. Backup with that method creates and stores fingerprint.db or data files for each guest machine. These files are written in the \Backup Exec\\Data folder by default.

The location where Backup Exec stores the fingerprint information can be shifted to a different local volume:  

Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes.
 

1. Browse to the following path:
   HKLM\Software\Veritas\Backup Exec for Windows\Backup Exec\Engine\HyperV Agent

2. Create a new String Value named  Finger Print Data

3. Change the Value Data to the lettered drive and path    (Example : D:\Program Files\Veritas\Backup Exec\Data\Hyper-V\)

4. Create a new DWORD Value named  Days Till Expire

5. Change the Decimal Value to the Number of days

Note:
Finger Print Data value is the location to store the Finger Print information.
Days Till Expire value is the amount of time to keep the Finger Print Data.