Tahoe not recognizing External Hard Drives that still work fine on Sequoia

I have upgraded my Mac Studio to Tahoe 26.0.1. Since the update, it refuses to mount any of my external Hard Drives, even if they have been formatted in APFS. I have tried to format them again from the MacStudio, and there is an error: "unable to mount". They were working perfectly fine up until the update. I have a MacBook Pro that I have not upgraded yet (still working on Sequoia), and that one recognizes the external drives without problem. They mount perfectly, and I can add and delete files normally. I have tried different ports and cables for the MacStudio to connect to the Hard Drive, but no difference. And they all work on the other Mac.

Any ideas why? It seems to be related to Tahoe, since it happens to all 3 of my external drives, but they all work in the one I have not upgraded yet, and they were all working until the upgrade. I have tried manually mounting them. I have used the Terminal and it says "successfully mounted," but it is still grayed out in Disk Utility and shows as not mounted. I have tried restarting several times, and I have checked for system updates and installed them all. Any ideas? Thank you!