Limitations and Restrictions of SharePoint and OneDrive

Limit 1 : A large number of items in a document library

SharePoint has a 300,000 item limit threshold for document libraries and lists, but it doesn’t cap your library at 300,000 documents instead it affects the performance of the library. Performance issues can occur if you have more than 300,000 items, even if you are not syncing all items.

Microsoft also says following for these:

• We may delay syncing of many files to ensure a high quality of service for everyone.
• There are other SharePoint limits on viewing a document library using the web that may affect how you structure your files in OneDrive.

Symptoms :

• Performance issues, slow library

• Unable to sync or complete sync (OneDrive sync constantly spinning the wheel)
• Unable to perform certain operations, like setting up unique permissions, set security, rename a file, move or copy
• Your computer fans sound louder than your hairdryer (if you are syncing this library to your computer)

To mitigate large item limit :

• Do not put more than 70-80,000 files and folders into a single library.
• Create multiple libraries, spread the content over multiple sites and libraries.

Limit 2 : SharePoint 400 Character URL limit

As you create folders and subfolders in a document library – the URL path to the content becomes longer and longer. The limit for the relative URL in SharePoint is 400 characters. Once you encounter the limit – you will start getting the error messages.

The 400-character limit includes the length of your site name, document library name, folders, and file. It does not count the characters in the domain/tenant’s name. For example, if the folder/document URL is https://sharepointmaven.sharepoint.com/sites/accounting/Shared Documents/Folder A/Document 123, it only counts the characters highlighted in BOLD RED above (starting with sites).

In addition to the above, if files are synced to a PC or Mac, the file/folder path can't be more than 255 characters due to operating system limitations.

Symptoms :

• You will start getting the error message above.
• You won’t be able to rename/create file/folder on your computer OneDrive.
• You won't be able to see some of the files synchronized as SharePoint online.

To mitigate SharePoint 260 Character URL limit :

• Create sites and document libraries with shorter names.
• Flatten the folder hierarchy within a document library (remove multiple layers of folders)
• Change the length of the folder and file names. Use Underscore/hyphen not space in the name.

Limit 3 : Windows 256 Character path limit

An even stricter limit you might encounter is the 256 character limit on your Windows PC. As users synchronize the document libraries to their PCs, they will encounter the error messages when trying to do anything within synchronized document libraries (i.e., create folders, rename documents, etc.). You will be able to create it online but when you edit it on Computer you will end up having sync issues with those folders and files.

Symptoms :

• Inability to create new folders within synchronized libraries – getting an error message above.
• Inability to create or rename documents within folders that take the path above the 256 limits in the synchronized document libraries.
• Inability to copy documents or folders into the folders that are taking the path beyond 256 limits in the synchronized document libraries.
• Sync Conflicts

To mitigate Windows 256 character path limit :

• Prevent sync for the document libraries.
• Flatten the folder hierarchy within the libraries.
• Consider using metadata in SharePoint.

Limit 4 : 300,000 item sync limits on OneDrive Sync

Another limit frequently encountered by end-users is the 300,000 limits on the number of documents users can sync using OneDrive sync client. As users click that sync button within their personal OneDrive and all the document libraries, the number of documents that need to be synchronized by OneDrive sync client increases. According to Microsoft, that limit cannot exceed 300,000 across all locations being synchronized. To be precise, it is not a strict limit, but more of a guideline. However, we have seen lots of issues with MHI devices encountering this. And since this is very common for a user to sync hundreds of thousands of files across many SharePoint sites/libraries, the issue pops up quite often.

Additionally, the same performance issues can occur if you have 300,000 items or more across all libraries you're syncing, even if you aren't syncing all items in those libraries.

Symptoms

• OneDrive sync not able to finish syncing (wheel spinning all the time)

• Sync conflicts
• Files not syncing to SharePoint and vice versa.

How to mitigate OneDrive sync limit

• Educate users about the limit (training!)
• Prevent sync on certain (larger) libraries.

Limit 5 : OneNote Notebook sync issues

OneNote notebooks have their own sync mechanism outside of OneDrive. If you plan on sharing a OneNote notebook—with yourself or others—it's best to create it on OneDrive right from the start. Moving an existing OneNote notebook into a folder synced by OneDrive without going through the OneNote application isn't currently supported.

References: 

Restrictions and limitations in OneDrive and SharePoint - Microsoft Support

SharePoint limits - Service Descriptions | Microsoft Learn