So I recently saw that Samsung Notes needed to upadte so I updated it immediately since it looked fresh and new.
I have Samsung Notes installed in Secure Folder too and updated it there. I didn't know that I would be unable to access older notes.
After I updated it, I wanted to open a locked note in Secure Folder containing my passwords, but it always told me that I needed to install an Add-On.
I was confused so I went to the Samsung Notes (not in Secure Folder) and tried opening up an old note, only to recieve the same message.
I managed to install the Add-On there though and now every time I open up Samsung Notes in Secure Folder it closes and I recieve a message saying that the app crashed.
I've tried clearing the cache and clicking on the three dots do I could access the "Convert All Notes" page, but it didn't work and now I can't even open the app without it crashing. Also, before I installed the Add-On in the Samsung Notes not in Secure Folder, I also tried going to the "Convert All Notes" page to convert the old notes, but it didn't work either.
(Sorry if this was long)
What type of device are you using, so I can provide you with troubleshooting steps targeted to your device and the symptoms you are experiencing?