Samsung PortableSSD Software can't be installed

Don't use the Samsung software. Use Disk Utility to manage the SSD.

What version of Samsung Portable SSD software did you try?

Version 1.74 is here:

https://www.samsung.com/semiconductor/minisite/ssd/download/portable/

Above based one:

https://forums.macrumors.com/threads/samsung-ssd-t5-driver-not-compatible-with-macos-monterey-help.2329885/

As stated, load the earlier MacOS that runs the software on an external drive, then decrypt using that temporary system. Then the Monterey use can resume. Very likely toe OP has moved on, successful or no, if nothing reported back.

Keith Barkley wrote:

Unfortunately, at this point he needs the Samsung software to *decrypt* the drive, and then he can use FileVault.

To the OP:

You might have to revert back to Big Sur to decrypt your drive.

Load Big Sur on an external drive for one-time use? System can run it.

I believe I had the Samsung Portable SDD software installed for Mojave and Catalina but I stopped using it since Big Sur (my two Samsung T5 500 GB SSDs are not encrypted).

I have a skeleton version of Catalina installed on an external SSD. It seems to require about 40 GB of space after installation. Perhaps installing Catalina to decrypt the SSDs is a good solution. As suggested, decrypting and reformatting with FileVault enabled may be the best option. I suspect you can perform all these steps in Catalina and then mount the SSD in Monterey.

- Pie Lover

Apple has been tightening the screws on third-parties altering the core system. Kernel-extensions are being slowly blocked, have been for years. In Monterey they locked core-system into a "sealed encrypted container". Even a very popular backup/clone utility called CarbonCopyCloner concluded hat keeping a dynamic clone of the core-system container was pointless under Monterey, and they now make only "point-in-time bootable clones instead.

From the lack of success running its encrypt/decrypt core-system extensions, under Monterey Samsung should have learned that the MacOS world is shifting and they need to to adapt, not the other way around.

I managed to open the SSD on an old Mac and remove the password which allows me to use the T5 on my M1 Mac, but obviously my T5 is now wide open. So now need to consider options for encryption/ password protection. Seems to me that Samsung’s software was password protecting that volume from mounting not encrypting the volume so looking for a similar solution.

Agree with previous posting regarding not using Samsung Software to Manage the External Drives. All too often, the third party software is buggy or not compatible of the version of macOS it is being attempted to be installed on. Case in point - what is being experience on this computer.

macOS is very able to manage most if not all External Drives without interference.

Format the drives using disk utility and then restore your data from your backup.

Contact Samsung and see if they have any suggestions.

You don't need the Samsung software to encrypt the drive. As already stated, use Disk Utility.

Unfortunately, at this point he needs the Samsung software to *decrypt* the drive, and then he can use FileVault.

To the OP:

You might have to revert back to Big Sur to decrypt your drive.

Much better idea!