Share via

Can no longer open old .xls files

Clifford WW 0 Reputation points
2026-05-13T10:59:10.8+00:00

I have a whole lot of very old Excel .xls files on my computer that I use consistently. They are my files, that I created (possibly from old templates) but this week I can no longer open them at all. I have tried every fix that I can find on the internet. I get that there are issues with security, and if I can open them now, I will save them all as .xlsx files, but I urgently need to get into these files to do so.

Microsoft 365 and Office | Excel | For home | Windows

2 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Xavier-D 8,585 Reputation points Microsoft External Staff Moderator
    2026-05-15T06:52:06.57+00:00

    Hello Clifford WW

    Has the answer provided by Q&A assist able to solve your issue?

    If not, I would like to add a few additional troubleshooting steps for you to try:

    • Make sure Excel is signed in with the same Microsoft account that previously opened these files successfully. Restricted files can fail to open if the current account does not have the correct rights.
    • Open one of the files and check whether Excel shows a message such as “This workbook contains a permissions policy” or gives you a View Permission option. That can help confirm whether the file is rights-managed rather than damaged.
    • If the file opens on another PC or under another account that still has access, remove the restriction right away by going to File > Info > Protect Workbook and removing any restricted access settings, then save a new unrestricted copy.

    If none of the accounts or devices that used to open the file can access it now, and the original author is no longer available, that usually points to a permission/licensing issue. In this situation, there may not be a client-side way to bypass the restriction.

    Feel free reply back to this post if you need further assistance, I'll be happy to help.

    Was this answer helpful?

  2. AI answer

    2026-05-13T10:59:32.33+00:00

    Use the following steps to regain access and then convert the files to .xlsx:

    1. Check if the files are actually corrupted
      If these .xls files previously opened but now do not, they may be corrupted or in a format Excel no longer recognizes. In that case, use Excel’s repair options:
    • Open Excel.
    • Select File > Open.
    • Browse to one of the .xls files.
    • Click the file once, then use the drop‑down on the Open button and choose Open and Repair.
    • If prompted, choose Repair first; if that fails, try Extract Data. For more detail on repairing workbooks, see Repair a corrupted workbook as referenced in the article below.
    1. Confirm the file format matches the extension
      If Excel reports that the format or extension is not valid, the file contents may no longer match the .xls format. In that case:
    • If the file came from email, save the attachment to the computer first, then open it from Excel instead of directly from the mail app.
    • If possible, ask the original source (if any) to resend in Excel Binary Workbook (.xlsb) or Excel 97‑2003 Workbook (.xls) format.
      Details are in the article about mismatched file formats.
    1. Check for corruption when stored in SharePoint/OneDrive
      If these files are stored in SharePoint or OneDrive and used to open correctly but now fail:
    • Download the .xls file to the local computer.
    • Try the repair methods listed above.
    • If the file still will not open, use version history to restore an earlier, working version:
      • In OneDrive/SharePoint, right‑click the file and choose Version history.
      • Pick an older version, select the three dots (more options), and choose Restore.
        Note: Restoring an older version will discard changes made after that version.
    1. If Excel hangs or says the format/extension is not valid
      For Excel for Microsoft 365/2021/2019, an issue where Excel prompts for access or reports invalid format has been fixed in newer builds. Update Office to the latest version and try again:
    • Install the latest Office updates as described in the referenced article.
    1. Once a file opens, convert it to .xlsx
      As soon as a file opens successfully:
    • Select File > Save As.
    • Choose Excel Workbook (*.xlsx).
    • Save under a new name to preserve the original .xls copy.

    If none of the above works for any of the .xls files, and they never open even after repair attempts and version restore, they are likely irreparably corrupted or in a non‑Excel format despite the .xls extension.

    References:

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

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.