SyncError:303 – Some file contents have not yet been uploaded

In short: SyncError 303 means that the content of at least one file is available on the device but has not yet been fully transferred to the sync target. This does not automatically mean that the file is damaged or lost. Initially, it simply means that an upload is still pending.

Depending on the synchronization method you selected, the sync target may be iCloud or a folder, for example. Here, “upload” generally means transferring the content from the device with the complete file to that target.

Which part of synchronization is still pending?

For every file, SimpleumSafe first transfers small pieces of file information such as its name, folder, and modification date. The actual file content is transferred separately afterwards.

With SyncError 303, the file content is complete on the device but has not yet arrived at the sync target. The message therefore always concerns the first part of the transfer route:

Safe on device A → sync target

A Safe containing three files on device A. The middle file is still waiting to be transferred to the sync target.
The file content is available on device A. Its upload to the sync target is still pending.
A Safe containing three files on device A above a sync target. The middle file is still waiting to be uploaded.
The file content is available on device A. Its upload to the sync target is still pending.

SyncError 304, by contrast, describes the state on a device that knows about a file but does not yet have its content. In that situation, either the upload to the sync target or the subsequent download to the receiving device may still be pending.

Why can this message appear?

Synchronization often ended too early on the device containing the complete file. This can happen if you close the Safe, quit SimpleumSafe, or lose the connection to the sync target before all file contents have been transferred.

On iPhone and iPad, iOS may suspend an app shortly after it moves to the background. A synchronization that is still running may then remain incomplete. Keep SimpleumSafe open on the screen until the app reports that synchronization has finished.

Other possible reasons include a slow connection, large files, or file content that was not correctly added to the list of pending uploads.

Why can 303 appear after synchronization was reported as complete?

Synchronization consists of several steps. File information may already have been processed while individual file contents are still being transferred or need another attempt.

At the end, SimpleumSafe checks whether uploads are still pending. SyncError 303 makes this unfinished state visible. Integrity Checker can also determine that file content available on the device is missing from the sync target even though no pending upload was shown previously.

How to complete the upload

  1. Use a device on which the affected file is complete.

    A file name shown normally indicates that the content is available on that device. A gray file name, by contrast, means that the content is still missing from that device.

  2. Open the Safe and check the connection to the sync target.

    Make sure the device is connected to the internet or to the sync target you use.

  3. Start synchronization again and allow it to finish completely.

    Keep SimpleumSafe in the foreground during synchronization on iPhone and iPad. Do not switch to another app, and if possible do not lock the device, until SimpleumSafe reports that synchronization has finished.

  4. Check whether the message appears again.

If the upload is still missing

Run Integrity Checker on the device containing the complete file. It can verify whether the file content is actually available at the sync target. If the content is missing there or was not added to the upload list, Repair can schedule it for transfer again.

  1. Start Integrity Checker:
  2. Read the result and the log. Select Repair if Integrity Checker offers this option for the finding.
  3. Allow the repair and subsequent synchronization to finish completely.
  4. Run Integrity Checker again. The finding should not reappear.

For an explanation of the possible results, see What do the Integrity Checker results mean?.

Do not delete the Safe or data at the sync target. If you cannot find a complete copy of the affected file or Integrity Checker reports Data Loss, create or retain a backup and contact Support before deleting anything.

When should I contact Support?

Contact Simpleum Support if:

  • the same finding reappears after Repair and another synchronization
  • you cannot find a device containing a complete copy of the affected file
  • Integrity Checker reports Data Loss
  • the connection to the sync target continues to fail

Include error code 303, the device and operating system you use, the synchronization method, and the Integrity Checker result. Never send your Safe password or recovery key.