What happen when SharePoint online list Unique permission limit crossed 5000 limit?

Since you have not provided any information beyond what the OP stated in his original question (that is, what he already knows), it's not likely he will continue to pursue the question here.

Hi respected Samadhan Kshirsagar,

I'm writing a follow up this case, and I haven’t received any information from you, may I know have you checked above reply? Feel free to post back if you need further assistance.

Have a good day and stay safe 😊

Sincerely,

Waqas Muhammad

Hi respected Samadhan Kshirsagar,

Thanks for your valuable feedback and sharing updates with us and I really appreciate your effort and your precious time doing. 

And I appreciate your kind words.

Yes, Microsoft recommends to have 5000 unique permissions but it can be increased to 50,000. Microsoft said, we should not increase the limit until we actually need it. For large lists/library, design to have as few unique permissions as possible. we need to design such a way so that we can keep unique permission below 5000.

Statement from Microsoft for unique permissions in list or libray level:

" Unique security scopes per list or library" - The supported limit is 50,000, but the recommended general limit is 5,000. Above 5,000, access control list (ACL) size starts to matter. Although you can add scopes up to the supported limit of 50,000, Microsoft doesn’t recommend it unless you have a very specific scenario in mind. For large lists, design to have as few unique permissions as possible."

Your understanding and patience will be highly appreciated. I hope that you are keeping safe and well!

Sincerely,

Waqas Muhammad

Thank you so much Waqas Muhammad MSFT for your response !!

Yes, we understood when we try to go over the 50,000 limits, SharePoint online will raise us an error "You cannot break inheritance for this item because there are too many items with unique permissions in this list".  We can't break permissions inheritance on library or folder.

So I have one more question , then why Microsoft is recommending 5000 limit that we will increase up to 50,000 limit.

What happen when SharePoint list Unique permission limit crossed 5000 limit*?*"

Thank You,

Samadhan

Dear respected Samadhan Kshirsagar,

Good day! Thank you for posting to Microsoft Community. We are happy to help you.

As per your description, as you know that there is a limit on the number of unique SharePoint online permissions you can set of 50,000 items per list or library. And this limit is officially presented by Microsoft. It is referred to as a "Security scope" limit for lists and libraries.

To answer of your question, "What happen when SharePoint online list Unique permission limit crossed 5000 limit?" when you try to go over the 50,000 limits, SharePoint online will raise you an error "You cannot break inheritance for this item because there are too many items with unique permissions in this list".  You can't break permissions inheritance on library or folder. You also can't re-inherit permissions on it. Microsoft also indicates that if you try to declare unique permissions after this limit has been reached you will be blocked from doing so.

The second aspect of this problem is the performance decrease. As the number of unique permissions in a list or library increases, you will notice SharePoint performance decrease even if you are not close to the limit yet. This might happen from around 5,000 unique permissions, although that will depend on your specific SharePoint implementation.

This affects any SharePoint environment that massively uses unique items permissions.

Try to organize your documents differently. The limit is set per list / library, so if you have more libraries, you are less likely to hit the limit.

Appreciate your patience and understanding and thank you for your time and cooperation.

Sincerely,

Waqas Muhammad