There is a known limitation in the default WebDAV driver for Windows. The maximum filesize is set to 50 MB and can be expanded to about 4 GB using a registry hack.
More information on how to change this setting can be found on the Microsoft Support website.
Be aware that changing the Windows registry is risky and if you decide to do so, it is on your own risk!
Instead, for transferring large files, we recommend to use the Cyberduck client (described above).
I'm willing to take that risk...
1. Open regedit
2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
3. Change the value of 'FileSizeLimitInBytes' to the maximum of 4294967295