'Not enough space on the disk' error when file compression is used

Hi,

I was trying the compression feature on a 48 GB dynamic drive, but it fails when copying a lot of files with Robocopy. Although it works if the files are not compressed.

The size of all files on the disk is only a little more than 20 GB, but Windows shows 47.9 GB of the volume taken space in its Explorer. My question is there is a way around that? I don't want to create a 48 GB static drive on a 64 GB computer.

Thanks in advance
Jean

Quote

The error log:

New File 761.6 m Environment_Structures.pak
2026/07/03 20:22:46 ERROR 112 (0x00000070) Copying File C:\SteamLibrary\steamapps\common\DuneAwakening\DuneSandbox\Content\Paks\Environment_Structures.pak
There is not enough space on the disk.
Waiting 2 seconds... Retrying...
New File 761.6 m Environment_Structures.pak
2026/07/03 20:22:48 ERROR 112 (0x00000070) Copying File C:\SteamLibrary\steamapps\common\DuneAwakening\DuneSandbox\Content\Paks\Environment_Structures.pak
There is not enough space on the disk.
Waiting 2 seconds... Retrying...
New File 761.6 m Environment_Structures.pak
2026/07/03 20:22:50 ERROR 112 (0x00000070) Copying File C:\SteamLibrary\steamapps\common\DuneAwakening\DuneSandbox\Content\Paks\Environment_Structures.pak
There is not enough space on the disk.

ERROR: RETRY LIMIT EXCEEDED.

Thanks for reporting this issue. We have found the cause, and it is now fixed.

What was happening: The error came from an interaction between NTFS compression and the way dynamic RAM disks were presented to Windows. When NTFS writes to a compressed file, it temporarily reserves space for the file's full uncompressed size as a safety guarantee (in case the data later needs to be rewritten in a less-compressible form). Dynamic RAM disks were reported to Windows as "thinly provisioned," and on such volumes Windows cannot guarantee that reservation - so it refused the write with "There is not enough space on the disk," even though plenty of space was free. That's exactly the ERROR 112 you saw.

The fix: We've released a new version that resolves this. Dynamic compressed disks now accept large-file copies correctly.

One thing worth knowing going forward: because NTFS makes that temporary reservation during every compressed write, the volume needs enough headroom for the uncompressed size of the file being written. Our recommendation is simply to create the RAM disk with a generous logical size, comfortably larger than the data you intend to hold. This "costs" your RAM nothing extra in practice: a dynamic disk only consumes RAM for data that's actually written (and compression reduces that further), so you can set the logical size well above 48 GB on your 64 GB machine without reserving that RAM up front.

The best approach for your scenario:

1. Create an image file as large as you want your RAM disk to be (Image > Create Image in the main menu).
2. Mount the image to a drive and either copy your files to it and then use the Compact command, or mark the drive as compressed and copy the files with Robocopy, whichever works better.
3. Once compression has settled, unmount the image (Image > Unmount Image in the main menu).
4. Create a RAM disk from that image file. Create it as usual, but select the image file instead of specifying a disk size. This way, both your game files and the entire file system are loaded directly from the image. There's no need to manually copy or recompress the files each time.