Welcome to the Community,
First thing to find out is whether it's a disk space issue on the host, or within the guest OS (assuming the 2.5GB is related to HDD space, and not to memory).
For how to find out about the free disk space, on the MACOS see e.g https://www.macworld.com/article/226152/how-to-check-a-mac-free-hard-drive-space.html, for the Windows 7 guest, open the Windows Explorer, right-click the drive, and select Properties.
André