If a file or folder is not synchronizing (not downloading/uploading or displaying old version), check if:

Unsupported symbols

Check the file/folder name. Mac application can upload files or folders with such names, that are not supported on Windows, so they cannot be downloaded.

To resolve the issue, rename the file/folder on Mac application. If the folder was shared, it should be re-shared after rename, because renaming will remove all shares and web links.

The following files cannot be synchronized:

  • Files starting with ~$ ?.tmp files ?desktop.ini ?thumbs.db
  • Files and folders that end with ".", ".."
  • Files and folders with names that contain the following characters: / or \
  • Reserved names: "CON", "PRN", "AUX", "CLOCK$", "NUL", "COM0", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "LPT0", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9"

Files and folders with unsupported symbols will be excluded from syncing and will look like this on Mac:

Excluded from syncing


  • The following characters <, >, |, *, ?, " that take place in file or folder name on Mac application will be automatically substituted for underscore (_) character, which is supported by Windows.
  • Spaces at the beginning and in the end of file or folder name will be automatically deleted

Cannot open new version

If the file is opened in another App (for example, Word or Excel), close this app to get the newest version of the file.


When trying to save a file locked by a collaborator, sync client remains in syncing state until the collaborator unlocks the file on his/her end.

Connection issues

SecuriSync Desktop application uses only HTTPS over port 443 to communicate with the server. This port is usually open for outgoing traffic.

Desktop app should be able to use HTTPS proxy that is set in Internet Explorer settings. If there is no HTTPS proxy and company allows only HTTP traffic, then Desktop app would not work.

Check if:

  1. port 443 is opened for outgoing traffic and HTTPS proxy is set in Internet Explorer settings (Internet options > Connections)
  2. sync.myonlinedata.net can be pinged (Start > Run > type cmd > type ping sync.myonlinedata.net)

If you have a firewall in place, make sure this URL is allowed.

Disk I/O error

Review SecuriSync logs to check if they contain disk I/O error:

TrayApplication | Unhandled exception occurred. | Cannot start service 'SpoolManager'. | Sync.Desktop.Core.Common.SyncException: Cannot start service 'SpoolManager'. ---> System.Data.SQLite.SQLiteException: disk I/O error
UploadFileTask | Task failed.  ServerPath: ''. LocalPath: ''. ItemID: ''. | disk I/O error disk I/O error | System.Data.SQLite.SQLiteException (0x80004005): disk I/O error

It means that file-system related problem occurred. A disk check needs to be performed.

File Extension policy is set up

Admin can specify files with particular extensions not to be synchronized in HostPilot > Services > SecuriSync > Settings > Backup policies. Read article on SecuriSync Settings for more information on policies and article SecuriSync: Which Extensions Will Not Be Synchronized With The Cloud? to see the full list of extensions.

Folder Path Exclusions

Admin can exclude file types that are not suitable for real-time backup. It is recommended to exclude large and frequently changed files for more information on folder path exclusions read article SecuriSync: Folder Path Exclusions (Admin Guide).

Folder is not selected for synchronization

User may chose, whether synchronize folder via desktop application or not. Read the Knowledge Base article on Folder Selection for more information.