Understanding Intermittent Sync Issues

An intermittent sync issue is when a working sync fails temporarily or intermittently.

Intermittent issues usually indicate a temporary condition is occurring that affects a particular run of a remote sync operation.

Common Causes

Intermittent issues usually occur due to changed conditions on the remote server. The most common issues tend to be related to timeouts.

Each sync has to compare the local files with the remote files. This includes the "metadata" about files and folders that you'll see in a typical folder listing - file size, timestamps, owner, and so on.

If sync is timing out then something on the remote server is taking too long to return a response.

A common cause of this is the size, width, and depth of the target folder on the remote server. That is, how wide and deep the folder structure is and populated by items it is.

If a target folder is significantly huge then it may take a long time to recursively list the structure for all the metadata.

Intermittent issues can also occur when target files become too big, when file names are temporarily changed to include unsupported characters, or when a target file is temporarily locked by the remote server.

Troubleshooting and Testing

As a test, you could try using our Desktop App to connect your PC to Files.com and access the remote server of a sync as a Remote Mount folder instead. In a Terminal/CMD window, try a recursive listing (ls -lR or dir /s) on the folder and see how long it takes.

Timeouts are typically 60 or sometimes 120 seconds. If the listing takes longer than that then you've found the issue.

Remediation

Try using a smaller target folder for the sync. Or use multiple syncs, each on a smaller subfolder, to achieve the intended results.

Where possible, rename file and folder names to remove any unsupported characters.

Avoid using source locations that contain locked files.