Since upgrading to 1.4 (1.4.75 to be exact) I'm having serious issues with Sync. When another process tries to update an existing file while Sync is running I regularly experience problems. Here are some reproducible situations: Sync & Innosetup: - Reproducibility: always Innosetup generates installers. When a previous version already exists it will first generate the new installer in a temp file. If successful it will replace the old version with the new one at the end of this procedure. However when this file is located in a folder managed by Sync the old file gets deleted, but Innosetup fails to add the new file instead it gives the following error: Compile Error: The process cannot access the file because it is being used by another process. The only way to use Innosetup in combination with Sync is to: close Sync, run Innosetup, restart Sync to synchronize the new file. Sync & 3DS Max: - Reproducibility: often but not always 3DS Max regularly saves to an autosave file. A few different versions are kept, but to prevent bloat the oldest gets overwritten each time a new autosave is made. When these are in a folder managed by Sync this process will regularly fail. Instead of autosaving 3DS Max will give an error indicating it was unable to write to the file. This happens with two separate Syncs one between four systems, another between three, all running 1.4.75.