Because of my slightly obsessive personality, I've been losing most of my productive time to a single little problem.
I recently switched from Mac OS X Tiger to Yosemite (yes, it's a fairly large leap). I didn't think AppleScript had changed that much, but I encountered a problem I don't remember having in the old days. I had the following code, but with a valid filepath:
set my_filepath to (* replace with string of POSIX filepath, because typing
colons was too much work *)
set my_file to open for access POSIX file my_filepath with write permission
The rest of the code had an error which I resolved fairly easily, but because the error stopped the script before the close access command, and of course AppleScript left the file reference open. So when I tried to run the script again, I was informed of a syntax error: the file is already open. This was to be expected.
I ran into a problem trying to close the reference: no matter what I did, I received an error message stating that the file wasn't open. I tried close access POSIX file (* filepath string again *), close access file (* whatever that AppleScript filepath format is called *), et cetera. Eventually I solved the problem by restarting my computer, but that's not exactly an elegant solution. If no other solution presents itself, then so be it; however, for intellectual and practical reasons, I am not satisfied with rebooting to close access. Does anyone have insights regarding this issue?
I suspect I've overlooked something glaringly obvious.
Edit: Wait, no, my switch wasn't directly from Tiger; I had an intermediate stage in Snow Leopard, but I didn't do much scripting then. I have no idea if this is relevant.
Agreed that restarting is probably the easiest solution. One other idea though is the unix utility "lsof" to get a list of all open files. It returns a rather large list so you can combine that with "grep" to filter it for you. So next time try this from the Terminal and see if you get a result...
lsof +fg | grep -i 'filename'
If you get a result you will get a process id (PID) and you could potentially kill/quit the process which is holding the file open, and thus close the file. I never tried it for this situation but it might work.
Have you ever had the Trash refuse to empty because it says a file is open? That's when I use this approach and it works most of the time. I actually made an application called What's Keeping Me (found here) to help people with this one problem and it uses this code as the basis for the app. Maybe it will work in this situation too.
Good luck.