【SharePoint Lists】Values Exceeding the Maximum Character Limit Can Be Saved in Grid View

As your issue description is primarily written in English, I will provide my response in English for your convenience. Please feel free to let me know if you would prefer the information in another language. 

Good day,

Thank you for providing the detailed reproduction steps, screenshots, and environment information.

Based on Microsoft documentation, a Single line of text column supports up to 255 characters, and the Maximum number of characters setting is intended to restrict user input to the configured limit. For example, Microsoft specifically cites scenarios such as enforcing a five-character employee ID field.

For reference: List and library column types and options | Microsoft Support

Given this documented behavior, values exceeding the configured limit would normally be expected to be rejected. However, I was unable to locate any public Microsoft documentation that explicitly addresses how character limits are enforced when data is pasted from Excel while using Edit in Grid View.

Based on the information currently available, I cannot confirm that this behavior is an intended product design. Since the value exceeding the configured limit can be saved successfully through Grid View, the behavior appears inconsistent with the documented purpose of the setting.

Here is recommended workaround: configure Column Validation

As an additional safeguard, you may consider implementing column validation to enforce the expected character length.

• Open the list and navigate to Settings > List settings.
• Under Columns, select the affected Single line of text column.
• Locate Column Validation.
• Configure a validation formula similar to:

=LEN([ColumnName])<=5

• Replace ColumnName with the actual column name.
• You can also define a validation message such as:

The value must contain no more than 5 characters.

Column validation can help verify that entered values meet the expected format and display a user-friendly message when the validation requirement is not met.

For additional information:

• Create a column in a list or library | Microsoft Support
• Examples of common formulas in lists | Microsoft Support

After configuring the validation, I recommend testing the following scenarios:

• Manual entry through the standard item form
• Direct entry in Grid View
• Copying and pasting data from Excel into Grid View
• Single-row and multi-row paste operations

This can help determine whether the validation rule is enforced consistently across all data-entry methods.

Power Apps option:

If the list uses a customized Power Apps form, you can implement additional validation logic that prevents form submission when the entered value exceeds the permitted length. However, this approach applies only to submissions made through the customized form and does not necessarily prevent changes made directly through Grid View.

Power Automate option:

A Power Automate flow can be used to detect items whose values exceed the permitted length and then notify administrators, flag the item, or perform automated remediation actions. Since such flows typically run after the item has already been created or modified, they are generally more suitable for monitoring and correction rather than preventing the save operation itself.

Existing data:

Because values exceeding the configured limit have already been saved successfully, you may also want to review the list for existing items that do not comply with the intended character restriction. Validation rules added afterward may help govern future updates but will not automatically correct previously stored values.

Product behavior and further investigation:

At this time, I could not find any public Microsoft documentation stating that bypassing a configured character limit through an Excel paste operation in Edit in Grid View is an expected limitation, nor could I find any publicly available roadmap item addressing this specific scenario.

Since the behavior has been reproduced by multiple users and across multiple lists, I recommend that your IT administrator open a support request with Microsoft and provide:

• List URL
• Affected column name (display name and internal name)
• Configured maximum character limit
• Detailed reproduction steps
• Sample Excel data used during testing
• Browser version
• Screenshots or screen recordings
• Confirmation that the longer value remains stored after refreshing or reopening the list
• Results of any validation-rule testing

I hope this information is helpful. Please feel free to share the results of the validation testing if you would like further assistance.

Thank you for your understanding, and I wish you a wonderful day ahead.

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