Restrictions and limitations when you sync SharePoint libraries to your computer through OneDrive for Business

INTRODUCTION

This Microsoft article contains information about the restrictions and limitations in using OneDrive for Business (formerly SkyDrive Pro) to sync SharePoint Online or SharePoint 2013 libraries to your computer.

MORE INFORMATION

Number of items that can be synced

You can sync up to 20,000 items total across all synchronized libraries. This includes OneDrive for Business libraries, Team Site libraries, or both. This includes folders and files. Separately from the overall sync limit, there are limits to the number of items that can be synchronized for each library type.

• You can sync up to 20,000 items in an OneDrive for Business library. This includes folders and files.
• You can sync up to 5,000 items in a SharePoint library. This includes folders and files. These are libraries that you find on various SharePoint sites, such as team sites and community sites, libraries that other people created, or that you created from your Sites page. You can sync multiple SharePoint libraries. Any team sites that you sync will also count against the overall 20,000 item limit across all synchronized libraries.

Size limit for syncing files

In any SharePoint library, you can sync files of up to 2 gigabytes (GB).

Character limit for files and folders

These limits apply to files and folders that you add to a synced library folder for uploading to SharePoint.

• In SharePoint Server 2013, file names can have up to 128 characters.
• In SharePoint Online, file names can have up to 256 characters.
• Folder names can have up to 250 characters.
• Folder name and file name combinations can have up to 250 characters.

Invalid characters

SharePoint Online

The following characters in file or folder names aren't supported when you sync OneDrive for Business with SharePoint Online:

\
/
:
*
?
"
<
>
|
#
%

Additionally, a file or folder name that begins with a tilde (~) isn't supported.

SharePoint Server 2013

The following characters in file name aren't supported when you sync OneDrive for Business with SharePoint Server 2013:

\
/
:
*
?
"
<
>
|
#
{
}
%
~
&

A file name that begins with a period (.) or a tilde (~) isn't supported.

Unsupported folder names

When you sync OneDrive for Business with SharePoint Online or SharePoint 2013, a folder named "forms" isn't supported at the root level for a list or library. This occurs because "forms" is a hidden default folder that's used to store templates and forms for the library. Additionally, a folder that contains the string _vti_ is reserved by SharePoint, and isn’t supported.
The following folder names can be synchronized in OneDrive for Business and SharePoint Online. However, if they’re synchronized, they won’t appear when you view the library on the SharePoint Online or OneDrive for Business webpage. With some of these restrictions, you may be unable to add files or folders that have these characters while in the OneDrive for Business folder. However, if you create the files or folders outside OneDrive for Business and then drag those files or folders into the OneDrive for Business folder, the files and folders will sync but the files won't appear on the webpage.

*_files:
*_Dateien
*_fichiers
*_bestanden
*_file
*_archivos
*_tiedostot
*_pliki
*_soubory
*_elemei
*_ficheiros
*_arquivos
*_dosyalar
*_datoteke
*_fitxers
*_failid
*_fails
*_bylos
*_fajlovi
*_fitxategiak
*_private

GUID strings as file names

The GUID string structure is supported in SharePoint Online.
The following GUID string structure isn't supported for file names in SharePoint 2013:

'{' + 8 hexadecimal + '-' + 4 hexadecimal + '-' + 4 hexadecimal + '-' + 4 hexadecimal + '-' + 12 hexadecimal +'}'

For example, a GUID that matches this structure resembles the following:

{9b6634a7-26b7-40a2-a48e-6f967d89c29e}

Invalid file types

You can't upload files that have a *.tmp or *.ds_store extension, and you can't upload desktop.ini, thumbs.db, or ehthumbs.db files.
Additionally, you can't upload files whose file types are blocked on the SharePoint site. If your organization is running SharePoint Server, the list of blocked files may vary, depending on what your administrator sets up. If your organization is running SharePoint Online, the default list of blocked files is fixed and can't be changed. To see a list of the default blocked files, go to the following Microsoft website:

File types that cannot be added to a list or library

Outlook PST files

Whereas PST files aren’t actively blocked by OneDrive for Business, syncing PST files that are in an open state isn’t supported. If you decide to sync PST files (for example, an archive PST file that you don’t load or view in Outlook), they can’t be in an open state at any time by any application while they’re in the OneDrive for Business sync folder. A PST file that’s connected to Outlook will be updated regularly and therefore if synchronized, can result in too much network traffic and growth of the Office File Cache on your local drive.

OneNote notebooks

Because OneNote notebooks have their own sync mechanism, they aren't synced by the OneDrive for Business sync client. You can upload OneNote notebooks to a SharePoint Online page. However, they won't sync with through the OneDrive for Business sync client application. Additionally, if you add a OneNote notebook to a local folder that syncs with SharePoint Online, the notebook won't sync with the SharePoint site and may cause other sync errors within the local folder.

Open files can't be synced

Any file that’s currently open by an application (for example, an Excel .xlsx file) can't be synced by OneDrive for Business.
To sync the file, close any application where the file is currently being used, and then sync the file.

Lookup columns in a library

The SharePoint Online or OneDrive for Business library can't exceed the lookup column threshold. For more information, go to the following Microsoft Knowledge Base article:

2927386 "We couldn’t sync this library" error when you use the OneDrive for Business sync client

"Fix it" tool to help in renaming files and folders to prepare or fix the naming of items in a local folder or OneDrive for Business folder

To get files to syncsuccessfully, you may have to rename a wide range and large number of files if their names contain unsupported characters. This Fix it tool for Windows automatically renames files and folders whose current names contain any unsupported characters. The tool also generates a report of those changes and of any files that are violating other restrictions that are called out in this article, and shows which folders were scanned by the tool.
Supported changes by this tool apply only to SharePoint Online. SharePoint Server 2013 may have a separate set of restrictions that were set by your administrator.
The Fix it tool currently performs the following tasks on the OneDrive for Business folder or local folder that you specify:

• Removes unsupported characters from file or folder names. For example, a file that's named This%is%a%test.doc will be renamed Thisisatest.doc.
• If an item has only invalid characters, it will be renamed Invalid Renamed File. If the item is a folder, it will be renamed Invalid Renamed Folder.
• If a file or a folder is renamed, and the renamed file or folder conflicts with an existing item on the same directory path, the item will be renamed by appending an <x> to the name. The <x> placeholder represents is an integer, starting with the number 1, until all rename actions are completed for that folder.
  For example, assume that a folder has two files that are named HelloWorld.doc and Hello%World.doc. Because % is an unsupported character, the second file is renamed HelloWorld.doc. To avoid duplication in the same folder, the name of the renamed file will be changed to HelloWorld1.doc.

In addition to file names being changed by this Fix it tool, several other rules are run to check for any additional limitations that you may encounter when it's syncing. A report that documents the issues that were found is generated and put on your desktop for you to review. A new log file will be generated every time that you run the Fix it tool.
The Fix it tool won't change file and folder names that have unsupported characters or generate warnings in the log file for the following items:

• OneNote notebook names
• Open files
• Lookup columns
• Maximum path character count for an uploaded file
  (The character count is not validated.)

To fix file and folder name problems automatically, click the Fix it button or link, and then follow the steps in the Fix it wizard.

More details and Download: https://support.microsoft.com/en-us/kb/2933738