Remote Assistance: Fixing Offer Remote Assistance

I'm researching Offer Remote Assistance currently and dang, we had about 54 things to fix before we got the process going. First, we had to take all sorts of steps to enable "Offer Remote Assistance" in Group Policy. Then, we had several SID related issues which created the following events in Event Viewer:

EventID: 2: A XML parsing error for ... occurred when attempting to process a remote assistance ticket.

We fixed that by changing the SID of the machine but soon ran into another issue:

EventID: 5251: The HelpAssistant account is disabled or missing, or the password could not be verified. Remote Assistance will be disabled. Restart the computer in safe mode and type the following text at the command prompt: sessmgr.exe -service.

This was addressed by running that as a startup script in Group Policy instead of running it in Safe Mode. Start -> Run -> gpedit.msc -> Local -> Computer Configuration -> Windows Settings -> Scripts -> Startup

Image not found

Web path:

Disk path: /static/images/startup-script.gif

Using Page Bundles: false

That totally fixed the 5251 error after a reboot BUT then we ran into another error. When we'd attempt to Offer Remote Assistance, there would be a partial login then the following pop-up would appear: Logon Message: You do not have access to logon to this session. In addition, the following error would be generated in the event log:

EventID: 5270: A remote assistance ticket has been created with duration: 0.08hrs for user

This was extremely time consuming to fix as there was no solution to this anywhere on the Internet. There were incredible attempts on usenet as seen here, but none of the solutions worked. So I loaded up the registry for a machine that successfully accepted Remote Assistance offers and a machine that didn't. I noticed a peculiar entry on the machine that didn't seem right:
HKLM\SYSTEM\CurrentControl Set\Control\Terminal Server\fInHelpMode was set to 1 even though the machine was not "in help mode" because it was broken. I deleted the key, restarted the machine and after months of trying, successfully offered remote assistance. This fix worked on all machines which encountered the "You do not have access to logon to this session" error. If you're searching for a fix on Google, I hope this works for you too!