Troubleshooting tips when regarding backing up your messages for upload to YoV
In general, all the applications mentioned in these support pages may require your device/Mac/PC to have enough available memory to carry out the backup task.
For examples, for both Mac and PC attempting to backup iMessages from an iPhone, the apps will often use a temporary directory to create the initial backup. Once that is done, the apps will give you the options to choose what you want to copy/save/backup so that you can upload them to versona.myyov.com for processing.
However, if your Mac or PC does not have enough space, you will have to cleanup your device.
Mac instructions for cleaning up or freeing up your storage:
Free up storage space on your Mac - Apple Support
PC instructions for cleaning up or freeing up your storage (works for Windows 11 as well):
How to Run Disk Cleanup in Windows 10 - YouTube