Bug introduced in 12.3, Resolved in 13.1

I am using Windows 10 and found a bug concerning NotebookDirectory (and also NotebookInformation) in 12.3. It can be easily reproduced. Create a new notebook and save it as notebook1 in a folder, lets say c:\folder1\notebook1. As expected, excecuting NotebookDirectory[] gives


Now save the notebook and copy it (using the Explorer) into another folder named c:\folder2. Rename the copy to c:\folder2\notebook2.nb and open it in Mathematica, such that now both notebooks are open. (There is no need to excecute notebook2.nb, just open it) The bug is, that re-excecuting NotebookDirectory[] in notebook1.nb gives:


instead of again c:\folder1 :-( This is of course not correct. I tested this on two machines, and saw the bug on both. Also I assigned different kernels to the notebooks. It does not matter.

Also, after closing and reopening Mathematica: If I open notebook1 alone I get the correct notebook directory, if I also open notebook2, I get for notebook1 the wrong directory.

With Mathematica 12.2 I had the problem not. However,I cannot exclude that the bug appeared with the latest Windows update.

Any ideas, what is going on?

  • 5
    $\begingroup$ I reproduced this problem (12.3, Windows 10), with an additional problem - if I then close the second file (with or without executing anything), and try NotebookDirectory[] in the first file, I get an error: NotebookDirectory::nosv: The notebook NotebookObject[25501141-5cf3-49a4-916b-3b8b6fb97d14] is not saved. $\endgroup$
    – MelaGo
    Jun 23, 2021 at 21:21
  • 2
    $\begingroup$ NotebookInformation[] reveals that both notebooks have identical ExpressionUUIDs. Is this the source of the problem? Or is this expected? I do not know what this ID is used for. $\endgroup$
    – dnet
    Jun 24, 2021 at 8:36
  • 1
    $\begingroup$ Now I testet this with 12.2 on the same machine. No problem there. ExpressionUUIDs are identical there, too. $\endgroup$
    – dnet
    Jun 24, 2021 at 8:42
  • 1
    $\begingroup$ As my colleagues and me copy notebooks containing NotebookDirectory[] rather commonly, we will go back to 12.2 for now. $\endgroup$
    – dnet
    Jun 24, 2021 at 8:51
  • 7
    $\begingroup$ I reported the bug to Wolfram. $\endgroup$
    – dnet
    Jun 24, 2021 at 9:01

2 Answers 2


I found an effective solution in this answer:


CurrentValue[$FrontEnd, FrontEnd`FrontEndObjectFormat] = "Legacy"

Thanks to josh and Kuba. In fact, we can find this "NotebookObject and CellObject now use a UUID string instead of specific FrontEndObject values" in incompatible changes of MMA. I think that's the problem.

  • $\begingroup$ I got the same hint from Wolfram support. And some hint that the issue might be solved in 13.1. Let's hope. $\endgroup$
    – dnet
    May 10 at 8:46

Sorry I can't make any comment because of my reputation.

Try with SetDirectory[NotebookDirector[]] as first line of you codeflow and then use Directory[] instead.

I had a similar problem and It worked for me.

  • 2
    $\begingroup$ It doesn't work. You solution relies upun buggy NotebookDirectory[], and hence can't work reliably in principle. $\endgroup$ Dec 9, 2021 at 4:14

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