Mac always times out when attempting to backup photos to Idrive

Old Toad said: "If you're trying to backup your Photos library to iDrive it won't work." A good point! A Photos Library can be archived on a Cloud Drive, but it needs to be pulled back to a local drive when needed for restoration. You can't rescue just a few pictures from a Cloud archived Library, because it can not be operated from a cloud drive.

So if it's the Library that you're trying to move to a cloud drive, and it's hard, then it may be just as hard to get it back to see the pictures. This is why I asked what you are really trying to do…

But you can export picture files to a cloud drive. Without the Library, it'll take some care to preserve albums and folders, and you will want both originals and edited versions, I would think.

If you're trying to backup your Photos library to iDrive it won't work. A Photos library must be stored on a volume that's formatted either APFS or OS X Extended (journaled). None of the commercial cloud storage facility uses those formats.

May I suggest a simpler solution: use a 2 TB bare OWC (MacSales.com) SSD connected via a SATA to USB adaptor like this:

You can quickly remove it in case of forced evacuation and keep it in a fireproof bag when not in used: COLCASE Fireproof Document Bag. I have several external bare SSDs that I use and can take with me in case of an emergency. This way you can store a copy of your Photos library on it and update it with Carbon Copy Cloner which does incremental backups, i.e. copying only those files that have been changed, added or removed. You can set CCC to backup whenever the destination SSD is mounted or, if left mounted all the time, on a schedule that you set, hourly or whatever.

It is possible to archive a Photos Library to iCloud, but it's not so obvious. And a large Library might run into similar problems.

You haven't really told us what you're doing. Are you trying to move the Photos Library to iDrive, or are you exporting pictures, or what? It sounds like you're not doing lots of individual picture files-- I'd think that you get it at least partially done, but it sounds like it's all or nothing. Almost always ( I think ) moving such huge files faces the reality that if one little thing goes wrong, you're doomed. I'd divide it up to smaller batches.

There are other cloud services, of course.