Failure adding assembly to the cache: Cannot create a file when that file already exists

So trying to add a Timer Job to the GAC causes:

“Failure adding assembly to the cache: Cannot create a file when that file already exists”

How do you get around it? well, try these things

1. if you have any dos windows/windows explorer windows in the assembly folder (or deeper) then move out of those folders (or close the windows down)

2. if you have Visual Studio open, and your project has a reference to your assembly, then you will need to close this down. Give it a while tho, even once your VS 200x has disappeared it is still unloading in the back ground

3. GacUtil /cdl – clears the assembly cache

4. do a IIS reset, if you have used the assembly in any web applications

5. reboot :'(

Thanks to Victor