cannot save excel files in excel for mac

Question

since today i cannot save my excel files anymore.

i use excel for mac 17.78.3 on macos tahoe 26.3.1

Answer 1

I believe what you cited as the Office Version Number is a typo — there is no such version but there is a 16.78.3 which is more than 2 years out of date. In fact, it precedes the introduction of Tahoe by more than a year.

The current build of Office is 16.107 but you may not be able to apply it because your version of Microsoft AutoUpdate most likely as obsolete as the software. If you go to Help> Check for Updates but get a notification that all apps are up-to-date you'll first need to retrieve the current version from this link: Download Microsoft AutoUpdate 4.82 Package

Answer 2

Try the following steps in order and test saving after each step.

1. Save with a new name and format

• In Excel, go to File > Save As.
• Choose a different folder (for example, Desktop).
• Enter a new file name.
• In File Format, choose a different Excel type such as Excel Workbook (.xlsx) (or, if already .xlsx, try Excel Binary Workbook (.xlsb) or Excel 97-2004 Workbook (.xls)).
• Select Save.

2. Check if the issue is file‑specific

• Create a brand‑new workbook: File > New Workbook.
• Enter some test data.
• Use File > Save and see if it saves.
• If new files save but existing ones do not, move the sheets to a new workbook:
  1. Open the problem workbook.
  2. Press Shift+F11 to add a temporary “filler” sheet.
  3. Select the first real sheet, hold Shift, select the last real sheet to group them.
  4. Right‑click a sheet tab > Move or Copy.
  5. In To book, choose (New book) and click OK.
  6. Try saving this new workbook.

3. Try saving in a different Excel file type

• Open the workbook.
• Go to File > Save As.
• In File Format, select a different Excel format (for example, .xlsx or .xlsm instead of .xls).
• Select Save.

4. Check for add‑ins or external components

• If saving works in some files but not others, or started failing recently, a third‑party component (for example, PDF or Adobe‑related add‑ins) may be interfering.
• Disable or remove any non‑Microsoft Excel add‑ins or integration tools recently installed, then restart Excel and test saving again.
• If an Adobe‑related add‑in (such as SaveAsAdobePDF.xlam) is involved, contact Adobe Support for an updated version compatible with the current macOS and Excel build.

5. If Excel itself is unstable or other Office apps also misbehave

• Quit all Office apps.
• Reinstall Office for Mac from the Microsoft account portal, then test saving again.

If none of these steps help and saving fails for all workbooks (new and existing), collect any error messages shown when saving and contact Microsoft Support, as the issue may be specific to the Excel 17.78.3 + macOS Tahoe 26.3.1 combination.

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References:

• Troubleshoot why Excel doesn't save changes
• Save a file in Office for Mac
• Are there known problems with Tahoe and Adobe - Microsoft Q&A
• Run-time error '53' - Microsoft Q&A