Can you transfer iPhone backups made on Windows to a Mac?
The backup format is the same for Mac and Windows, so you can copy your backup from the C:\Users\[USERNAME]\AppData\Roaming\Apple Computer\MobileSync\Backup folder on your Windows computer to ~/Library/Application Support/MobileSync/Backup on your Mac yes. If you need instructions for various versions of Mac and Windows to access these folders, here's a blog post I wrote with them.
If you have a USB thumb drive, that may be better to copy the 50GB backup. :) You could also right-click on the folder for the backup and select Send To &gt; Compressed Folder first to zip it.