Excel HTTP Error 400. The size of the request headers is too long

Anonymous
2024-01-25T17:23:24+00:00

Good afternoon,

Today I was helping a user, Alice, change a picture in the header of an excel workbook. When Alice clicks the "picture" button in the ribbon under the "Header and footer" tab, instead of showing the dialog to pick a file to insert, the window that pops up says "HTTP Error 400. The size of the request headers is too long" with no other information.

Notably, if Bob, another user with an apparently identical account and user profile, tries to follow the same steps on the same computer as Alice, Bob is able to do so without receiving the error message.

We have tried the following:

Reinstall office365

Sign out of user account and back in

Split the document into smaller documents in case it was a file size issue

Running the repair tool for office365

Thank you!

Edit:

Good morning! I am happy to say we found a solution! Unfortunately it was to reinstall Windows.

Microsoft 365 and Office | Excel | For business | Windows

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Anonymous
2024-02-01T11:11:15+00:00

Good afternoon,

Today I was helping a user, Alice, change a picture in the header of an excel workbook. When Alice clicks the "picture" button in the ribbon under the "Header and footer" tab, instead of showing the dialog to pick a file to insert, the window that pops up says "HTTP Error 400. The size of the request headers is too long" with no other information.

Notably, if Bob, another user with an apparently identical account and user profile, tries to follow the same steps on the same computer as Alice, Bob is able to do so without receiving the error message.

We have tried the following:

Reinstall office365

Sign out of user account and back in

Split the document into smaller documents in case it was a file size issue

Running the repair tool for office365

Thank you!

the following solution is also possible:

file - account - settings management - turn off optional online functions and done

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  1. Anonymous
    2024-01-26T05:15:14+00:00

    You may try deleting this folder to reset Excel (Close all the Excel first). It will recreate automatically.

    Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Excel

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  2. Anonymous
    2024-01-25T20:03:35+00:00

    Update, had her try it on another computer and she was able to do so with no errors. It is specific to her account on THAT computer as far as we can tell.

    We also tried it with a brand-new blank workbook and got the error message.

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  3. Anonymous
    2024-01-25T18:55:47+00:00

    Is it possible to change to another network for testing?

    Have you tried logging in Alice account on another computer?

    Unfortunately we are stuck with the network we are on in this case, it's a desktop without wifi capability and we only have one network available.

    I will have Alice try signing in to another computer on the network and get back to you.

    In the meantime, if she does not get the error when signing in to another machine, what would you recommend we do next to diagnose the issue on her own computer? What about if she does get the error on another machine?

    Thanks for your help!

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  4. Anonymous
    2024-01-25T18:43:42+00:00

    Is it possible to change to another network for testing?

    Have you tried logging in Alice account on another computer?

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