If the virtual disk is full, try to reclaim some disk space, possibly by deleting temp files.

Shut down the VM cleanly.

1. Shut down the VM
2. Take a snapshot
3. Resize the VHD in XenCenter
4. Boot the VM
5. Extend the volume in Windows Disk Manager

xe vm-list
xe vdi-list name-label=<vm-name>
xe vdi-resize uuid=<vdi-uid> disk-size=<new-disk-size>GiB

Windows Disk Manager → Select Disk → Extend

In linux, we first extend the partition then the filesystem. LVM would add a step or two…

growpart /dev/sdx 3 resize2fs /dev/sdx3

or another appropriate command for the used filesystem type.