Every directory on my RAM disk is 'read only'

Every directory on my RAM disk has a Read-Only (only applies to files in folder) attribute set, which is causing problems.
I'm running Window 11 Pro 25H2, with RAM Disk 25.10 [x86_64], mounting an image at start-up.
What is continually setting this attribute and is it possible to stop it doing so?

Also, can one enable Dynamic allocation and TRIM functionally from within the app?

RAM Disk only presents block storage to Windows. The read-only attributes are being applied by NTFS/exFAT or another system component, not by the RAM Disk driver itself.

For initial diagnostics:

1. Test with a fresh image: Create a new blank RAM disk image (freshly formatted) and check if the read-only attributes appear on directories in this new image as well.
2. Disable security software: Temporarily disable antivirus and any backup/sync utilities (OneDrive, Dropbox, etc.), then remount and check if the read-only attributes are still being set.

To identify exactly which process is setting these attributes, you can use Process Monitor from Microsoft. Open Process Monitor and create a filter for your RAM disk drive letter. Look for operations containing "SetFileInformationFile" or "FileBasicInformation". This will show you exactly which process is setting the read-only attribute and when.


As to Dynamic allocation and TRIM, yes these work with both volatile and image-backed RAM disks. To enable, simply tick them in the disk properties:

Regarding RAM Disk 25.12, what does the dark blue band at the bottom represent? I haven't found any information to explain this. A label, like "Free" and "In Use" segments have, would be helpful.

With regard to Process Monitor, it's not obvious how to create a filter for A:\. Are you able to tell me what I need to do?

And, for RAM Disk, what is required for compression to save disk space to be enabled?

The blue band represents the space occupied by RAM disk(s). You will see that it's equal to the RAM disk(s) size combined, unless you are using dynamic allocation, in which case it would show the dynamically changing memory usage.

In Process Monitor, create the filter as follows:

Path - Begins With - A:\ - Include

To enable disk compression in RAM Disk, navigate to RAM Disk Properties → Advanced → Enable compression to save disk space.

Regarding the directories with the Read-Only (only applies to files in folder) attribute set, I was only able to find "SetEndOfFileInformationFile", and surprisingly, the files that I checked the attributes of, didn't have the Read-only attribute set! I also discovered this Read-Only (only applies to files in folder) attribute is also set for Directories on C:\, so it's obviously a Windows system problem. Thanks for your help with this problem.

I've now determined that one can only enable compression to save disk space, by creating a disk, and selecting NTFS as the File System, under File System Options, and not creating an image. I assume compression works as the label says. Compressed when written to disk, not when in RAM.
My own testing of the compression feature reveals that it is disabled as soon as an image is associated with the RAM disk. If that is correct? And if so, how does one save the RAM disk data to disk using compression?
I discovered that compression is a Windows feature, that can be enabled within the Advanced properties of any NTFS directory or file. If enabled, the data in the RAM disk would be compressed wouldn't it? How would this affect an image? Would an image the size of an uncompressed RAM disk be required, because the compression ratio isn't fixed? Is this why compression is disabled when an image file is added to a RAM disk?

To answer your question about why the compression option becomes unavailable when using an image file: the compression feature is implemented as an NTFS file system attribute. When enabled, NTFS transparently compresses data as it is written to disk in the background. For this reason, the option is only available when the RAM disk itself is formatted as NTFS.

When an image file is used, all NTFS attributes and file system metadata are stored inside that image. In this scenario, compression cannot be controlled at the RAM disk creation stage. If you require data compression while using an image file, you can enable NTFS compression after the disk is mounted by selecting one or more folders (or files) on the mounted drive and setting the compression attribute directly.

The there will likely be less disk space required to store the image file because the data will be compressed. Image files are stored as sparse files, so their logical size is always greater than the on-disk size. It is, however, important to note that NTFS compression has additional CPU overhead and it temporarily reduces disk's free space as a file is first copied uncompressed and then it's compressed in the background, so additional space may be required.