Desktop client - sync of large file fails with error: Insufficient space

Simple question that I can’t find the answer to anywhere - when syncing a large file via the desktop client, does the server require twice the storage space available of the file being synced?

I’m trying to sync a 51GB file to a partition with around 80GB available and it fails with a message in the log about insufficient space.

The sync process seems to upload chunks of about 60MB into a holding folder. Does this then build the final file whilst keeping all the chunks until it’s finished? I can’t see why else it would be failing.

The most frustrating part of this is that once the process fails, the holding folder gets emptied and the sync starts all over again giving me no chance to try and remedy things.