Box Sync has a technical limit of 40,000 synced items (including folders and files). However, for optimal sync performance, we recommend around 10,000 items.


If files aren’t syncing to your computer, first make sure that you have marked folders for Sync through the web application. Sync will not automatically download all content from your Box account—you must first designate particular folders for Sync.


 Here are a few common incompatibilities that will prevent items from syncing down to your computer:


Blocked file types
The following file types are blocked and unsupported by Sync:

  • Temporary files and folders (.tmp and files/folders starting with ~ character)
  • System and hidden files
  • Windows shortcuts
  • Box WebDocs
  • Outlook PST files
  • QuickBook files
  • Google Docs/Spreadsheets


Long file paths
Windows does not allow file paths longer than 256 characters. For this reason, Box Sync for Windows will not download any files that result in a path length of more than 256 characters. To prevent this, we recommend avoiding deep folder hierarchies and long file names. The full path of Microsoft Office documents includes the drive letter, and all characters and folder names up to and including the name of the document. The entire path cannot be longer than 242 characters in Word, or 218 characters in Excel.


Mac bundles
Many files on the Mac are stored as "bundles", which is a folder that OS X is able to interpret as a file. This includes many iWork files, Mac Apps, NIBs, and more. Box Sync will not upload these files to your account.


Blocked characters
Box Sync does not support files or folders that contain any of the following characters:

   / * ? " : < > |

If you attempt to sync files or folders containing these characters, Box Sync will prompt you to rename the file or folder using the underscore character. In most cases, we recommend pushing the “Rename” button and accepting the renamed file or folder that Sync suggests.

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Source: Information Technology Services Help Desk
Telephone: 215-204-8000Location: TECH Center - Room 106
Website: email:
Last updated: 01/17/19
Related keywords
Box Sync
Storage Policy

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