In a couple of scripts that I use I have problem that is intermittent.
Sometimes the script fails when trying to delete a file. According to the error log due to the file being accessed by an other process. I'm guessing that windows not had time to release the file after the previous operation performed on the file ended.
What amount of time would be a good guesstimate after which windows should have had time to release the file again?
If the Windows app is done working with the file it should be closed instantly, because presumably they closed their file handles. There is no delay in time to unlock a file after a file close operation.
If a program forgets to close their file handles though, but ends, Windows will free it for them (just not instantly). Usually it's not long but it can be any amount of time, I haven't seen it take longer than a couple seconds. But proper cleanup should be done to avoid it being locked.
It's also worth mentioning that not all programs open files in a locked way. They can open file specifying what type of access they'd like to give other processes, and they can also lock portions of the file. They may open the file with full read/write permissions to other processes.
If you have no control over the process that is not closing its file handles, but you need to execute it, you could write some kind of loop to keep trying the file for a few seconds.
As another user has posted, it should be done instantly if the file has been closed correctly - with an indetminate delay until the OS sorts it out otherwise...
Always, always dispose of resources correctly.