NovaBACKUP PC/Server/Business Essentials software requires 3GB of free disk space on C: drive in order to operate.

With the software completely closed, and no backup operations running, you can cleanup some temporary files on the machine in a few locations.

Make sure the following tasks are not running using Task Manager: 

drdiag.exe | nsCtrl.exe | NovaBackX.exe | nsService.exe

You can pretty much remove anything in the following directory except the .db and .dbx files. 

NOTE: This will empty the Logs tab of the software as well.

C:\ProgramData\NovaStor\NovaStor NovaBACKUP\Logs 

You can safely remove everything in these locations: 

C:\ProgramData\NovaStor\NovaStor NovaBACKUP\Temp
C:\ProgramData\NovaStor\NovaStor NovaBACKUP\vData
C:\ProgramData\TempDR

If you specified a different path for the Temporary files to be stored (using the Default Settings area of the software "Advanced" tab, more information here), you can remove anything in the same final directory from there as well (Temp and vData).

If you are using the NovaBACKUP Cloud (xSP) client: 

In your xSP device folder, you can remove everything in here: 

C:\ProgramData\NovaStor\NovaStor NovaBACKUP\<xSP device name>\Backup

Additional Steps to Save Space

The NovaBACKUP software will automatically compress some files when they are created, related to the file selection list for Logs, and the Restore Media Index records (in v16.5.1215 and newer). This saves quite a bit of space, on the order of 10:1 compression.

You can confirm if this information is being stored as compressed by enabling the Windows File Explorer view option named "Show encrypted or compressed NTFS files in color" (blue files are compressed).

C:\ProgramData\NovaStor\NovaStor NovaBACKUP\Data\Media
C:\ProgramData\NovaStor\NovaStor NovaBACKUP\Index
C:\ProgramData\NovaStor\NovaStor NovaBACKUP\Temp
C:\ProgramData\NovaStor\NovaStor NovaBACKUP\Logs

You can manually Enable Windows file compression on these Directories by right clicking on each of them, select Properties, click [Advanced], and adjust the setting option "Compress contents to save disk space". The folder should turn a blue color after you click [OK] on the dialog(s).

Test out creating a backup job so that you can see the new log file save out as a compressed file and to make sure the TEMP folder is setup correctly, keep an eye on that newly specified TEMP files path if you changed it.

There are additional utilities that you can utilize to "visualize" the space usage on your NTFS drives, such as WizTree or WinDirStat, but they are outside the scope of this article.