How to increase Character Limit for Multiline Text Field in SharePoint Online (Microsoft Lists)

Hi Philipp,

Refer to Multiple lines of text, A Multiple lines of text column can store up to 63,999 characters by default. There’s no settings you need to change to allow more than 255 characters. Based on my test, it also works well for Microsoft List.

The “allow unlimited length” option is only in library UI. That is because, only library needs it. Refer to SPFieldLookup.UnlimitedLengthInDocumentLibrary property:

1. Columns with long text are not supported by most applications for editing documents and could result in a loss of data.

2. Only allow unlimited length if users will be uploading documents through the Web site, and not saving directly from the application.

For example, based on my test:

1. If I enable “allow unlimited length” option in library, and if I have more than 255 characters in file property, my Excel files cannot be opened correctly with Excel desktop application.

2. If I disable “allow unlimited length”option in library, my Excel files can be opened correctly with Excel desktop application, however, if I have more than 255 characters in file property, I cannot save the file from Excel client app to SharePoint Online.

Please feel free to post back if you still need help.

Regards,

Rena