The \AppData\Local\Temp location is the system default TEMP and TMP location for Windows 11 and is what Pegasus Mail uses if not otherwise specified in PMAIL.INI. The Help > About > Info button will tells what the environment variables are set to but not what Pegasus Mail is actually using as its temp location. I have suggested that it be included if possible.

As for -ROAM, no, you don't need to be using it.

I have not seen any other report of insufficient space warnings by 4.81 so I don't think it was ever on David Harris's radar to fix. I'm fascinated by this issue though because I can not upgrade to the latest IERenderer (2.7.2.6) using its installer because it abends due to being unable to read the registry entries it checks. The installer for 2.7.2.4 still works fine. AFAIK, I'm the only person with this problem. I do not have any doubt that the issue is with my system but am clueless why. Speaking of IER, @meska , have you updated? Also know that IER has a location for its image cache. You can see its path in IER configuration. FWIW, I use C:\Temp\PMail and C:\Temp\IERCache for temp locations.

I just heard back from the ultimate authority, Mr. David Harris, on the insufficient space warnings. He said,

There's a bug in the way some versions of Pegasus Mail calculate free space
that can result in this type of error when there is a very large amount of free
space (can't recall the exact number OTTOMH, but it's in the terabytes).
Oddly enough, I would have thought v4.80 would have had the same
problem...

The problem is fixed in current codebases, I just can't distribute them until I
get the pmail.com problem sorted out.

I hope the bug he refers to is relevant and explains what is happening.

Yes, I have 2.7.2.6 installed. Its cache path was D:\PMAIL\MAIL. I’ve changed it to D:\TEMP\IERCache just like you suggested. Thanks for contacting Mr. David Harris. It makes sense: I do have almost 2.8 TB on D: drive, and 800 GB on C: drive free. I’m glad the problem is known and is being addressed.

Think the insufficient error is probable caused by a variable that doesn't have a large enough size to support the free space. Use to give students a program that has a loop using a char (1 byte value). Worked fine with values up to 127, since a signed character handles -128 to 127. unsigned character has range of 0 to 255. Signed character value of 127 goes to -128 if you add 1. So, probable Mr. Harris used a variable type that at the time seemed fine, but now needs to e changed to a larger size.

My first computer was a HeathKit H120. Cost $2300 as a kit, and had option of a 20M hard disk, but it was an additional $2000. So I had dual 320K floopies (Before that upgrade to 360K) Was only making $12,000 a year teaching back in 1983.

Should be a simple fix.

Could also be a function call that returns value, that doesn't handle bigger drives.