All the code code is static, it doesn't change. I have about 10 active tasks, but most run daily or weekly - only one runs every few minutes. It makes more sense that only one temp folder would appear, the script shouldn't need to be recompiled every time. Do you know what triggers the module to recompile?

Exactly, it should only create one folder to prevent recompilation. I found some discussions here here here where some folks notice the files get locked by the process (in your case that would be the IIS web process) and couldn't delete the files. If you run it slower like every 10 minutes, does it still create the folders? Have you tried restarting IIS?

I found those posts as well, not sure it's related. In your test was the folder getting deleted and rebuilt each time? Or was the same DLL being reused each time the script ran? Something is causing my system to recompile the code each time.

The code explicitly checks to see if a precompiled cached version exists and won't compile again. On my system, it doesn't create multiple folders on subsequent scheduled runs of the same code.

FYI - Just had a look in my temp folder and there seems to be a new razor folder roughly every day. Among the files inside is always a cs file that appears to be from the Revindex task scheduler as it contains the code from the task that I have on the server for Xero updates. I have that running once per day, so that fits.

Each of the folders has it's own unique name e..g. RazorEngine_5k3op2gq.icw

So yes, I can confirm I'm also seeing folders there, and if the task ran more frequently or on more portals, then there'd also be more folders.

It's certainly not cleaning up after itself.
Rob