I was once using Mathematica 11 it all works fine - when I create new Notebook (.nb) input like 1+1 and press shift+enter, it shows output[1]:= 2 directly

But now for 12.1 when I create new notebook and do the same thing, it is treating my input 1+1 as plain text by default, when i press shift+enter there is just a linebreak.. no evaluation at all.

I find when I go to the menu -> cell -> cell properties and tick Evaluatable then the input can work well as Mathematica 11. BUT when i input Plot[x,{x,1,2}], it gives output -Graphics-!! Without showing what the graphic is! I then have to manually convert the output cell to StandardForm to show the graph! I have to do such things everytime, why is 12.1 getting me so much ados ..and how can i remove such tedious things making it funcation just like what mathematica 11 does?

Pardon me I'm a complete nooooooob and really searched goooogle tons of times not getting the answer....


1 Answer 1


These strange behaviors can be produced by:

  1. SetOptions[EvaluationNotebook[], FrontEnd`ReturnCreatesNewCell -> True] (or, in MMA 12+, just SetOptions[EvaluationNotebook[], ReturnCreatesNewCell -> True]since ReturnCreatesNewCell is now defined in the System` namespace).
  2. SetOptions[$Output, FormatType -> OutputForm] or SetOptions[EvaluationNotebook[], CommonDefaultFormatTypes->{"Output"->StandardForm}]

It's quite strange for a new Wolfram Mathematica installation to be like this. I'm not sure which situation you are in and whether there are other problems.

If you haven't made any major changes from a new installation, then I think the problem is likely due to the stylesheet. Try to set the stylesheet of the notebook to Default.

  • $\begingroup$ Its true the stylesheet everything going back2 normal when set to default... .thx $\endgroup$
    – gudako
    Nov 22, 2020 at 4:04
  • $\begingroup$ I am confused about your statement about SetOptions[EvaluationNotebook[], CommonDefaultFormatTypes->{"Output"->StandardForm}], it has two meanings. Do you mean that (a) the CommonDefaultFormatTypes defines no other options except "Output", or (b) That the CommonDefaultFormatTypes option list contains "Output"->StandardForm among other rules? (b) is the default in MMA 12.x and 13. Also, IMO, it would be a bit clearer if you could provided non-destructive queries the OP could perform, e.g. Options[EvaluationNotebook[], ReturnCreatesNewCell] for the item 1, etc. $\endgroup$
    – kkm
    Jun 1, 2022 at 12:46
  • $\begingroup$ @kkm My aim is to make minimal change to the system, so I've used the nested syntax of queries. $\endgroup$
    – asd1dsa
    Jun 3, 2022 at 12:59

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