I have a problem that does not seem to be posted previously, and seems to have started after I upgraded to Mavericks. I am working with a large notebook (about 150 pages, 35 MB) and about every half hour, I get a spontaneous "Why the Beep?" window that says "The notebook's file … has changed outside of Mathematica. The notebook has been renamed to Untitled-7. Mathematica has a complete record of changes made to the notebook, but might not be able to recover some of the unchanged cells. You can open the existing file again to reconcile any unsaved changes."
When I look for changes, Some of the cells that were in a closed state have been emptied. I open them and see Null. It's as if MacOS 10.9 is doing memory management improperly, and does not recognize some of Mathematica's memory state as being in use. Has anyone seen this type of error message, especially when working with large notebooks? It is not affected by other applications being open; it occurs even when Mathematica is the only application in use.
I have experienced the same problem occasionally (MacBook Air, OS X 10.9.3, Mma 9.0.1) — maybe once a week for me — but I have never checked to see what has changed in the notebook. I always close without saving, and then revert to my previously saved version, which is OK for me as I am a habitual Command-S addict. I haven't yet noticed any particular conditions that correlate with the occurrence of this problem.
re: "The notebook's file … has changed outside of Mathematica." message
It is erratic and it goes back to 10.8. A few of us here encounter it annoyingly often. I have never encountered loss of data.
For now, the workaround is to turn off checking for notebook changes outside of Mathematica. The steps are - open the Option Inspector (under the Format menu), - Set scope to Global preferences - in the lower part of the window, * click Notebook Options * click File Options * click FileChangeProtection * click the box-with-triangle to the right of the option name * in the menu that opens, select None. See the attached screen shot.
I do NOT want to disable the warning, because what it warns of is real damage. A couple of times I thought nothing had changed and I saved my file, not realizing that the "closed" cells were not only closed, but erased. That meant a lot of lost work, and I had to recover older versions I had backed up. This kind of hazard does not seem up to the standards of either Apple or Wolfram, but is more reminiscent of using an early version of Word on a Windows machine where you develop a habit of hitting Command-S every few minutes as self-defense.
I am glad to hear others have experienced this problem, at least. How can we get it fixed, for real?
"How can we get it fixed, for real?" - Figure out what triggers it.
Developers and testers have spend two years on it and it is still elusive.
I have now noticed that Time Machine activity seems to be correlated with the appearance of the "The notebook's file … has changed outside of Mathematica." message. I have seen several instances where this message dialog pops up whilst TM is doing its work, and I haven't noticed any instances of the message dialog when TM is NOT doing something. However, this message dialog appears only rarely (for me, that is) — i.e. it doesn't occur every time TM does a backup.
Good observation. Thank you.
Not the case for my Mac, but it might have something to do with the problem. I will pass it on.