Bug introduced in 10.0.0 and fixed in 10.1

UPDATE: Now both the inputs "\б" and "\\б" are interpreted as "\\б" and displayed in OutputForm as "\б", InputForm["\б"] returns "\\б" and StringLength["\\б"] returns 2.


"\бвгд" // FullForm
"\\бвгд" // FullForm

In v.8.0.4 I get this:


But v.10.0.0 adds redundant backslash before the first backslashed Cyrillic symbol:



As the result it is not possible to open any file which name (or name of a directory in the path) starts from a Cyrillic symbol.

Also after evaluating the above (in the case the Cyrillic symbols were typed, not pasted in the Notebook) the following bugs appear:

  • When I try to cut by pressing Ctrl+X any Cell or group of cells in this Notebook I get http://demonstrations.wolfram.com/ opened in my browser and nothing changed in the FrontEnd

  • After some additional editing (entering backslashed Cyrillic symbols after the quote " but without entering the closing quote and without evaluation of the cell) an attempt to cut an input cell by pressing Ctrl+X results in commenting all the code in the selected input cell. Pressing Ctrl+X again uncomments the code.

All the above manipulations with Ctrl+X give this result when English keyboard locale is selected.

Does anyone also observe this? Is there a workaround?

P.S. OS Win7 x64.

  • $\begingroup$ I think this may have to do with the change to a single system font. In previous versions, '\б` or other Cyrillic character would not replace \ with \\, whereas this would happen with Latin characters (as long as they weren't escape sequences). This was true in v9 as well, but in v10 letters from both alphabets behave the same. Does the single slash not work for you? On Win 8.1 x64 (v10) this works fine for me: Import["алексей\попков","Text"] > привет! $\endgroup$
    – mfvonh
    Jul 14, 2014 at 14:57
  • $\begingroup$ One workaround for Import is to use FileNameJoin. $\endgroup$ Jul 14, 2014 at 15:30
  • 2
    $\begingroup$ I'm not an expert but I don't think "\\:0431\:0432\:0433\:0434" is properly formed -- that is, I think the bug is in V8.0.4 (and V9.0.1, too). If I paste the string in V8.0.4 and execute it, the output displays as nine characters, \:0431вгд, which seems the proper interpretation (compare with StringLength["\бвгд"]). A similar thing happens with other unicode characters. That it used to work suggests offsetting bugs or intentional flexibility in processing resource-locator strings. Similarly, the V10 string "\\\\:0431\:0432\:0433\:0434" seems to be missing a backslash. $\endgroup$
    – Michael E2
    Jul 14, 2014 at 16:09
  • $\begingroup$ @Michael It sounds like we have bugs both in versions 8,9 and in v.10 but now the things become worse: filename handling is broken. $\endgroup$ Jul 14, 2014 at 17:51
  • $\begingroup$ I usually use FileNameJoin anyway, or do you mean it's not working? (Btw, I don't have Windows, so I can only check the filename string in Mma; I can't check whether the file can be opened with the string.) $\endgroup$
    – Michael E2
    Jul 14, 2014 at 18:00

1 Answer 1


For file operations two workarounds currently work:

1) Use slash / instead of double backslash in the paths to files under Windows:

Import["D:/test/кириллическое название/файл.txt"]

2) Use FileNameJoin or StringJoin:

Import[FileNameJoin[{"D:", "test", "кириллическое название", "файл.txt"}]]

Import[StringJoin[{"D:", "\\", "test", "\\", "кириллическое название", "\\", "файл.txt"}]]

Note that both produce just ordinary double-backslashed output:

FileNameJoin[{"D:", "test", "кириллическое название", "файл.txt"}]
"D:\\test\\кириллическое название\\файл.txt"

Manipulations inside of the Kernel are safe:

path = File /. FileInformation["D:/test/кириллическое название/файл.txt"]

"D:\test\кириллическое название\файл.txt"

(Import works as expected).

But copying this and pasting into the FrontEnd gives a string that is parsed incorrectly:

Import["D:\\test\\кириллическое название\\файл.txt"]
During evaluation of In[12]:= Import::nffil: File not found during Import. >>


So it is clear that this is a FrontEnd bug.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.