Every CSV I've ever tried to save from Excel (2010, anyway) says filename.csv may contain features that are not compatible with CSV (Comma delimited). Do you want to keep the workbook in this format?. Why is this? Is there any way to save CSV files from excel that do not contain this message?

Even the following file (saved as a .csv) will cause this to happen, if you try to save it:


I've even just created a new spreadsheet in excel and tried to save it, and it still shows this message.

I wouldn't care, but I have someone telling me that I'm not formatting CSV files properly because excel shows that warning message, and I'm looking for ammunition to prove it's Excel and not my format (or if it actually is my format, to fix it).


Microsoft Excel will claim this when saving to just about any format other than .xls or .xlsx. The reason is that only these (proprietary Microsoft) formats can support Excel features like formulas, (conditional) formatting, charts, multiple worksheets, etc.

If all you're saving is data, you can safely ignore this message. I think you can even tell Excel to shut up and stop telling you that with a little "Don't show this warning again" tickbox on that "error" message.

To the person criticizing "your" CSV formatting, I'd shoot back that it's Excel, not you, generating the CSV file, so any error in the CSV format is Excel's error, not yours.

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    Unfortunately, there's no "don't show this warning again" tickbox. In fact, the whole error dialog is actually hard to read, and actually looks like it's from Excel 97. The CSV being generated is actually from my application, but I get the error even when excel generates its own CSV, so I just wanted to figure out why. – gregmac Apr 7 '11 at 18:36
  • Ah, well then the response I'd give your critic is a) Excel opens your CSV files just fine, and b) your CSV files look just like those containing identical data generated by Excel. A shame you can't silence that error, though -- it's obnoxious! – Kromey Apr 7 '11 at 18:38
  • I agree it's annoying, though with older versions, I think it was 2000 and before, there were two question you had to answer before you could save a CSV. Then when you close it it asks you if you want to save it, even if you have! – paulmorriss Apr 8 '11 at 8:24

Looks like there is a way to fix this, I just found this article, which worked for me using Excel 2013.

Registry subkey 
Value name  DisableSaveAsLossWarningOpenDocumentSpreadsheet
Value type  DWORD
Value data  0 - Display the warning message
            1 - Suppress the warning message

The registry value changes to

DisableSaveAsLossWarningOpenDocumentPresentation for Powerpoint and
DisableSaveAsLossWarningOpenDocumentText for Word
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    Assume linkrot. (That is, the link you point to might not work anymore in a few years, or maybe even tomorrow). That leaves this post as an unuseable answer. Thus please copy all relevant parts into the answer and make sure that you are allowed to do that. – Hennes Nov 6 '15 at 15:15
  • any way to do this on mac? – alex Mar 4 '16 at 21:54
  • @alex Don't have any idea about mac setting – Pranav Kulkarni May 30 '17 at 10:37

The features that Excel is complaining about are settings and functionality like cell formatting, column filters, formulas, and other Excel specific functionality that won't be saved when you save to a CSV.

For example, if you had a cell that contained a formula, such as =2+2, only the evaluated value of 4 would be stored in the CSV, the formula itself would be lost.

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