Duplicate iCloud sync stores and Sync.log file size

Hi, DevonThink is my current go to solution for organizing research and administrative information. I have steadily accumulated a large collection of materials and use iCloud for synchronization between two desktops and two iOS devices with DevonThink to Go installed. Local databases are stored on an external drive. This works really well; however, as the size of databases grow so too the cache in ~/Library/MobileDocuments … /DevonThink (268.8 GB) and other hidden files such as Sync.log in Cloudy (10 GB??). Unfortunately, Apple’s design decision to make the local iCloud sync store non-relocatable to a different storage device means that a certain point one iCloud sync just become impossible to use further. I have 5GB of room left on the system drive. Part of the issue seems to be a set of database duplicates that cropped up over time in iCloud. So, I have two questions.

  1. How can duplicate iCloud sync stores on local databases be safely identified and removed to eliminate needless duplication? The local databases only amount to 61 GB, a small fraction of the size of the storage sync for these databases on iCloud.

  2. Why is the Sync.log file in Cloudy so large. 10GB seems enormously excessive. Is there a safe way to trim that file down?


I’m having similar problems. I have asked in another post if we could get more information about how sync works so we can understand these issues.

I’d really like to see more status information for debugging. It’s all “black box” and difficult to debug.

I find the iCloud solution to be very unreliable. I understand the fault lies with Apple but I have very low confidence that things are synched and rely on check files created just to detect sync failures.

I love DTG with a passion and want to be able to trust it. I’m very worried that I’ll silently lose files.

Why not use one of the non-iCloud alternative means of sync? Or two of them?

Good question. I pay for Apple iCloud disk space but don’t want to pay for DB or one of the others. I’m retired and money is an issue.

Maybe I’m missing something, I’d love to use direct sync to my own sever over the internet, that would be ideal. But they don’t let us specify the host by IP address or DNS name, just bonjour.

So I limp along with iCloud.

Of course, although switching from iCloud to another sync solution imposes its own costs. (Good I am stuck at home and have a bit of extra time!), nor does switching address the issue of the multiple duplication of synced databases within iCloud (61GB of databases somehow ballooning to 268.8 GB) and the seeming difficulty of cleaning all this up. Apple’s insistence on the shadow mirroring of iCloud files is an issue only Apple can rethink. Hopefully, the duplication of databases by DevonThink is just a rare quirk.

Maybe you can set up your own free WebDav server

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Sync.log is usually a quite small file (few KB up to several MB). If it’s really that huge then you’re experiencing lots of sync issues. This could also explain the used disk space in ~/Library/Mobile Documents as macOS & iOS should evict the local files after up-/downloading.

You could try to verify the sync store thoroughly (see contextual menu in Preferences > Sync after pressing the Alt modifier key), this should also remove the local copies. And you can of course delete the log file, a new one will be automatically created.

Thank you for the clarification. I moved sync to Dropbox for the time being and—eventually—cleaned up the iCloud sync store with a trip to the office computer and turning off iCloud for DevonThink to Go on my devices. So far, so good. With luck whatever issue that led to the duplication of databases on iCloud will not occur again.