File is already open error

I often run into this error when saving packed experiments: Window title = "Save experiment file Error"; Message = "While finishing experiment file safe save: The file is already open."

The error is intermittent; in files where it happens once, it often happens in the majority of my save attempts, and it will usually save successfully in a small proportion of attempts. It occurs when re-saving a (packed experiment pxp) file under the current experiment name; it never happens in files that I have just saved under a new name. Sometimes, during repeated save attempts, files with the name [myPXPFileSaveName]T#.pxp (where # = 0,1,2... up to n-1 copies of this nature) start to build up in the destination file. It also seems like it might tend to happen more often when saving larger files (for example, most recently I was having difficulty with it on a file of ~150 Mb) and/or with multiple instances of Igor open, though I haven't tracked it carefully enough to be sure.

I'd be curious to know whether it might be possible to fix or avoid this problem (without having to save files as a different name and then later rename them to the name I'd like)? I'm using Igor 7 (7.01 build 28061), but I have had the problem just as often with Igor 6.xx. Please let me know if further information would be helpful.
I've seen this myself when saving an experiment that's in a directory mirrored to my Google Drive. The same thing might happen with other cloud storage services that have a way to synchronize files on your local disk to the cloud. You can also get this behavior due to an antivirus program scanning the temporary file that's created as part of a safe save.
Ah, I am also usually saving to a mirrored drive, so that might be it. Thanks for pointing that out. Now I'm curious to know if this happens with other programs or just Igor Pro (I don't recall such issues in saving large files with other programs), and more generally if there are methods of saving in place that avoid the problem.
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Now I'm curious to know if this happens with other programs or just Igor Pro (I don't recall such issues in saving large files with other programs), and more generally if there are methods of saving in place that avoid the problem.


It does happen with other programs. The problem is that some other software, typically a virus scanner, security software, or some kind of cloud storage software, opens the file while Igor is trying to save it. The issue is discussed here: http://support.microsoft.com/kb/316609. Igor uses the retry mechanism recommended in the document but it does not always work.

I don't know of any foolproof solution other than to disable virus scanners for Igor extensions, if that is possible, or to save to a local volume if the problem is cloud storage.