It was mentioned in 0321 thread that the bug is marked as closed meaning this will probably never going to be fixed.
https://github.com/GrapheneOS/os-issue-tracker/issues/2847

Can you who don't have this issue write your model, when first installation was and when it became fixed?

Has anyone made any full reinstall and saw this issue fixed?

I am running Pixel 7 with 0321 version and this still happens to me 100% of the times.
The fingerprint sensor shows for 0.2 seconds and then dissappear. Only way to unlock main profile after switch is through passcode always.

I tried removing all prints, tried disable, reprogram fingers but issue still persists.

Considering the upcoming 2nd factor feature with finger+pin I think this issue should be more prioritized to be fixed.

    JayJay Looking at the issue report, it was closed as "completed", meaning that it is assumed to be fixed. It was closed after my report, and because there have been no other reports in the issue after that, it is still regarded as fixed. You can make a comment in the issue. Preferably providing info about your device, OS version and any custom configurations that might be applicable.

      JayJay

      I thought it was fixed (after one recent update I suddenly got fingerprint working whenever I switched profiles, but after another update (or just a reboot?) it stopped working again 100% of times.

      Could you please post a link to the issue in the issue tracker? May be worth posting some comments there to get some attention to the issue (or trying to fix it ourselves)?

        (I mean a link to AOSP issue tracker, not GrapheneOS one)

        bayerelm
        I had the same problem and because my three apps, which actually require Google Play services, now run quite well without Google Play services, I had deleted the user profile I had created for this purpose.

        I have just created a "Google profile" for testing purposes and saved a fingerprint.
        Now everything works as expected!

        After the first change, there was a brief problem as described by one of you (fingerprint symbol only appears very briefly, then GOS wants the password again).
        But since then, the lock symbol changes to the fingerprint symbol after two seconds at the latest every time the profile is changed and logging in then really works.

        However, I have now only stored one fingerprint in the second profile.
        There was (is?) the other problem that the second/each additional profile cannot remember more than one fingerprint.
        I will test whether this problem has been solved later.

            Eagle_Owl
            Addendum:
            I added a second fingerprint to the second profile and then switched between the profiles a few times.
            Conclusion: Works great, only takes about 1-2 seconds for the lock symbol to change to the fingerprint symbol and then you can put your finger on it and you're logged in.
            That's how it should be! :-)

            Tested with my Pixel 7 Pro, newest GOS version 2024032100

                Eagle_Owl

                Oooh, thanks for the hint as this has been bugging me like crazy!

                It's definitely an improvement getting the fingerprint working again when switching from owner to new profile. But not the other way around and also not all the time. It's like the phone is going through a process of thinking and showing the print, then it just stops and locks up URGH

                  Eagle_Owl
                  how many fingerprints have you stored in main profile?

                  I have 4 stored in main and 4 in second.
                  I tried deleting all fingers in second and re-added however it didn't help.
                  Using pixel 7 nonpro.

                      JayJay
                      Two fingerprints on both profiles.

                      Only two, because I had the problems before.
                      I may have problems again if I save more than two fingerprints per profile.

                          Eagle_Owl
                          Addendum:
                          Especially for you, I have now tested again and saved two more fingerprints in the owner profile only.
                          Result: The problem is back!

                          I then deleted the additional two fingerprints and tested them again.
                          Result: Everything works!

                          Conclusion: there must be the same number of fingerprints stored under all profiles or at most two per profile will work.

                          But I'm not going to test this any further. If one of you has already saved the same number and/or the same fingers per profile anyway and it doesn't work, we already have the answer: then only two fingers per profile are currently possible.

                              Eagle_Owl

                              Ohhhhh snap. I had five fingerprints in the main and five in the second profile. I deleted three in both profiles so left with two (math...)

                              Still early, but it seems to be allowing the fingerprint unlocks now when switching...

                              Holy crap, if this works...you freaking legend

                                Eagle_Owl

                                You are the king!
                                My phone had limits for max 4 per finger and I used up all slots for both profiles.
                                I deleted all and added
                                3 in main + 1 in second
                                That didnt work.

                                I did 2 in main + 1 in second and it worked! This is the first time it starts to work for over 9 months!!
                                I added 3 again i main, and it stopped working.
                                So seems there is some sort of limitations here or bug when adding more than 2 prints per finger.

                                Also I want to add when switched profile first time back to main it asked for my pw, but after that all attempts worked with fingerprint only.

                                For a split second it shows lock symbol if you let it run the fingerprint sensor will show up. If not for whatever bugged reason just turn screen off and on (i have power button to instant lock phone enabled) and it does show up.

                                I will report back again here in a day or two with my verdict :)

                                BIG THANK YOU!

                                  Eagle_Owl
                                  It's amazing you figured this out. You should get a reward. lol. Thank you, thank you, thank you.

                                    After 5 hours of constant switch back and forth I can tell it still works fine with having just 2+1 prints added (should work same as 2+2 also). Also tested some reboots meanwhile.

                                    The only bad side-effect of being limited to 2 fingers per profile is due to the bad fingerprint reader of Pixel 7 (which has nothing to do with GOS), I used to add multiple configuration for same finger to have a 100% success rate unlocking the phone.
                                    With the limitation of just 2 fingers added (1x thumb and 1x index) I am now having difficulty of reader to scan my finger as my thumb now requires 2-3 attempts to unlock it. But I am still happy :) To have this resolved was the biggest inconvenience with gos ever.

                                    You should update the GOS bugtracker and maybe this can be fixed finally. All creds to @Eagle_Owl for the time you spent and finding a workable solution.

                                    Another thing I noticed now regarding this issue is that if you have too many incorrect attempts on one of the profiles with the fingerprint, then the fingerprint also gets disabled in the other profile (change profile through lockscreen) and it asks for pw there too. Once pw is is entered the fingerprint starts to work again.

                                    So somehow it seems some information regarding fingerprint configuration/settings or something else is shared among profiles hence the limit and workaround regarding the 2+2 fingers.
                                    If this helps any DEV.

                                    Unfortunately, this workaround only works partially for me. I have stored one fingerprint/profile (no more than four in total). If I switch back and forth between several active profiles, it works well.

                                    But if I exit a user profile via "end session" and switch to the owner profile (which is actively running in the background), the fingerprint icon only flashes briefly, but then disappears again and I have to enter the password again each time.

                                      Has anyone tried 5 prints in all profiles to see of that works too ?

                                      Murcielago
                                      What happens if you inside main profile start an app that can be configurated to use fingerprint to access app. For example bitwarden.
                                      Does everything start to work again?

                                        matchboxbananasynergy

                                        Eagle_Owl
                                        I tried two profiles with 5 prints and couldn't use finger print when switching profiles . went down to two prints and it works as it should . this is crazy .
                                        Should repot google , maybe a bounty ?
                                        I added more prints when my finger got disfigured must of been around that time it stopped working correctly .