Can't stop excel from opening hundreds of windows for pdfs and spreadsheets

Frustrated 20 Reputation points
2026-01-19T20:07:26.8366667+00:00

After restarting my laptop, I clicked to open excel. Immediately hundreds of windows started opening with questions of if I wanted to still open the file or telling me it's unsafe. I've tried:

~ the command and comma key trick but I can't get preferences to open

~ gone to the excel app on Launchpad and trashed everything in containers.

~ emptied the trash.

Across the spreadsheets that opening it has an alert that there was "possible data loss." I'm at a loss and the exact question I'm asking has been asked before in the spring of 2025 but Microsoft has closed the question.

Somebody HELP, please. I don't have however many days it could take to answer "no" to all of the questions and window popping up.

Microsoft 365 and Office | Excel | For business | MacOS
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Answer accepted by question author
Anonymous
2026-01-20T02:26:56.0466667+00:00

Hi Frustrated

Thank you for reaching out to Microsoft Q&A Forum and sharing your experience.

I understand how disruptive this can be, especially when Excel repeatedly opens hundreds of warning dialogs and won’t allow you to access Preferences or dismiss them efficiently.

In this situation, you can try the following steps.

First, force quit Excel completely:

  • Press Command + Option + Esc on your keyboard, select Microsoft Excel, and choose Force Quit.
  • If Excel does not close, open Activity Monitor (Spotlight > type Activity Monitor), select Microsoft Excel, then select X > Force Quit.
  • If your Mac still cannot restart because Excel remains “busy”, press and hold the power (Touch ID) button for about 10 seconds to force a shutdown.

Next, try launching Excel in Safe mode:

  • Make sure Excel is completely closed. Press and hold the Shift key, then while holding it, select the Excel icon to open the app. Continue holding Shift until the main Excel interface (template gallery or a blank workbook) fully loads.

Since PDFs are opening automatically in Excel, also check the Excel startup folder:

  • In Finder, press Command + Shift + G, then paste the following path: ~/Library/Group Containers/UBF8T346G9.Office/User Content/Startup/Excel/
  • If any files are present, move them to the Trash.

Although you mentioned clearing containers, please also double-check the AutoRecovery folder to ensure no corrupted recovery files remain:

  • In Finder, press Command + Shift + G, then paste: ~/Library/Containers/com.microsoft.Excel/Data/Library/Preferences/AutoRecovery/

After completing these steps, restart your Mac and then open Excel again to check whether the issue with returning windows still occurs.

Additionally, to help better understand the issue, could you please provide the following details:

  • Is your Office content synced with OneDrive, and does pausing OneDrive sync change the behavior?
  • Are any add‑ins or citation tools enabled in this file, and does Word close normally when you open a brand‑new blank document?
  • Which versions of Word and macOS are you currently using?

Please know that while our initial response might not resolve the issue right away, your input is incredibly valuable. With a bit more detail, we’ll work together to find the best solution for you. 

I am looking forward to seeing your response soon.

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  1. AI answer

    2026-01-19T20:07:39.9833333+00:00

    To stop Excel from opening multiple windows for PDFs and spreadsheets, you can try the following methods:

    1. Remove files from the XLStart folder and alternative startup folders: This folder may contain files that are automatically opened when Excel starts. To do this:
      • Open the Run dialog (press Windows + R), and type the following paths to access the XLStart folder:
        • For Office 365 or Office 2019 32-bit: C:\Program Files (x86)\Microsoft Office\root\xx\XLSTART
        • For Office 365 or Office 2019 64-bit: C:\Program Files\Microsoft Office\root\xx\XLSTART
        • You can also check %appdata%\Microsoft\excel\XLSTART and C:\Users\UserName\AppData\Roaming\Microsoft\excel\XLSTART.
      • Delete any files in the XLStart folder or move them to another folder.
      • Restart Excel.
    2. Start Excel in Safe Mode: This prevents all Excel add-ins, toolbar customizations, and startup folders from loading. To start Excel in Safe Mode, hold down the CTRL key while starting Excel, or use the command line with excel.exe /safe.
    3. Check for alternative startup folders: If you have set an alternative startup folder, make sure to clear it by going to File > Options > Advanced and locating the General section. Clear the box next to At startup, open all files in:.
    4. Repair Office: If the issue persists, consider performing an Online Repair of Microsoft Office. This can fix corrupted components that might be causing the problem.

    If these steps do not resolve the issue, you may need to explore further troubleshooting options or consult Microsoft support for additional assistance.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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  2. Bob Jones AKA CyberTaz MVP 438.6K Reputation points
    2026-01-20T03:00:46.9066667+00:00

    I don't believe anything offered so far will be of any value. It sounds like a simple Preference setting which does require a bit of critical timing — it may take more than one try.

    1. While Excel is not running, launch the program & immediately press Command+Comma to launch the Preferences dialog
      1. if Preferences doesn't open use Option+Command + esc to Force Quit the program
      2. Be sure to clear the checkbox to Restart the program
    2. If the Preferences dialog successfully opens go to the General pane then clear the field for At startup open all files in:
    3. Restart Excel

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  3. Frustrated 20 Reputation points
    2026-01-20T22:11:32.36+00:00

    Thanks for your response! I went through all of the steps above probably three times with each bringing the same result: I can now get the template screen with excel, however, one of the boxes pops up (which will start the problem all over again if I click it). I never can get to the system preferences to make an adjustment to what it opens upon launch. To answer the additional questions you asked:

    • is your Office content synced with OneDrive, and does pausing OneDrive sync change the behavior? I am not synced with OneDrive, I don't use it.
    • Are any add‑ins or citation tools enabled in this file, and does Word close normally when you open a brand‑new blank document? Not sure which "brand new blank document" you're referring to so I'll answer to both. Word does not close when I open a new document in Word, nor does Excel when I open a new spreadsheet. Before all of this, they both worked perfectly.
    • Which versions of Word and macOS are you currently using? Word 16.105, and macOS Sonoma 14.6.1

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