Error C000009A

Again it's an odd error that indicates a resource shortage (not necessarily memory).

Perhaps try with a different file system and the Hard Disk Emulation option on and off?

If the above doesn't help, try using a logon-time disk instead of boot-time one or vice versa.

If still no luck, what about two RAM disks of 4000 MB each?

If the version of Windows is newer than 17134.228, for example 17738, there is a problem with one disk of 4096 MB:
NT error code = C000009A: Недостаточно системных ресурсов для завершения вызова API (translation: insufficient system resources exist to complete the API)
Image status = Image load succeeded.
Win32 error code = 0 Операция успешно завершена (translation: operation completed successfully)
4 disks of 4 000 MB are mounted.

Windows build 17738 is an Insider Preview. From our experience, things are often broken in preview builds, so we'll check how it works when the release is out.

In the post of 22 June 2018 there was a discussion mentioning Windows build 17692. The problem arose after the build 17666. Everything was fine before that.

Likewise, builds 17692 and 17666 are insider previews. Unfortunately since insider previews often have bugs, we can only investigate the problem if makes it into an official release.

Tomorrow (or the day after tomorrow) will release a new version of 1809 Windows 10. And what? Will you make a postscript on your website: "SoftPerfect RAM Disk. Only for older versions of Windows 10"?

Once the official release is out, it will be possible to run the tests and determine which, if any, problems are present. Your wish to have everything predicted and taken care of in advance is understandable, but unfortunately, not practical. Only Microsoft know what the release is going to contain, and too often even they get surprises; hence the perpetual stream of updates and bugfixes they issue.

Out preference is for quality over quantity, i.e. less frequent but stable releases, to avoid bombarding our users with tweaks and patches made for half-baked preview OS versions.

I updated Windows to Build 1809 and got the same problem now
I normally use the freeware version 3.4.8, but even the latest trial version does not work anymore

We have investigated this issue where only disks smaller than 4096 MB could be created in the newest builds of Windows 10.

It turned out Microsoft has suddenly changed memory limits in their allocation routines. In tech-speak, there is a function called MmAllocateNodePagesForMdlEx, where Microsoft documentation states:

Quote

The maximum amount of memory that MmAllocateNodePagesForMdlEx can allocate in a single call is (4 gigabytes - PAGE_SIZE). The routine can satisfy an allocation request for this amount only if enough pages are available.

This seems to be no longer true as of Windows 10 v1809, and the function fails to allocate the maximum amount. We will release a new version of the RAM Disk with this fix in a couple of days.

Well, that was Release Windows 17763.1. SoftPerfect RAM Disk more than 4 GB does not work with it. Let's start pondering what to do?

Came here to say this... Windows 10 v1809 -- I cannot mount a 12GB image. Glad a fix is coming, thanks for a quick response to this.

Regarding the errors and problems with RAM disks larger than 4GB after Windows 10 update to v 1809, please see this thread.

We have identified the issue (no thanks to Microsoft) and found a solution, and will release a RAM Disk update in a few hours, once all the drivers are signed and tested with the new Windows version.

Thank you all for your cooperation and patience.

RAM Disk version 4.0.8 has been released and can now be downloaded from RAM Disk home page. It contains the fix for the Windows 10 1809 problem that caused errors for RAM disks larger than 4 GB.

Before updating, please check your free update period in the RAM Disk's About menu.