Their website also advertises a special version of the software specifically for Big Sur users, but I did not find this was necessary to use. Install the 'normal' Portable SSD software from the Samsung website.sudo rm -rf /Library//StagedExtensions/Library/Extensions/SamsungPortableSSDDriver.kext.sudo rm -rf /Library/Application\ Support/PSSD_Installation.sudo rm -rf /private/var/db/KernelExtensionManagement/AuxKC/CurrentAuxKCA/StashedExtensions/17A3D6DA-575D-40F2-B1EC-59FD1CB31623 (I checked what was in each of the StashedExtensions subfolders and found the one that had Samsung Portable SSD stuff).cd /Users//Library/Application\ Support/Portable_SSD/.YMMV and you might not have to run all these steps. Here is the sequence of steps I finally came up with that fully removes all traces of the PSSD software and got me back to a working state. In turn, the reinstalled software doesn't work / doesn't have the correct permissions to access the SSD. Therefore, when you try to reinstall the software, macOS doesn't prompt you to approve the security exception for the software in System Preferences -> Security & Privacy. The root issue appears to be that none of the suggested solutions actually does a full removal of the Samsung Portable SSD software.
