It’s been a long time since I launched Portainer, but I ran into a problem where my pihole container wasn’t loading, and I needed to fix it. I tried logging in with the password I thought I used, but it didn’t work. Several other attempts to log in also failed.

At that point, I turned to the web for help. It ends up that Portainer has an official helper-reset-password tool.

Stop my Portainer instance:
docker stop portainer

Validate my Portainer data volume:

root@pi5:/# docker volume ls | grep portainer
local     portainer_data

Get the helper-reset-password tool and run it:

root@pi5:/# docker pull portainer/helper-reset-password
root@pi5:/# docker run --rm -v portainer_data:/data portainer/helper-reset-password
{"level":"info","filename":"portainer.db","time":"2026-09-01T22:38:35Z","message":"loading PortainerDB"}
2026/09/01 22:38:35 Password successfully updated for user: admin
2026/09/01 22:38:35 Use the following password to login: b({aJ=)y@cU/9Z|H4lNi1FEG2eK85[06
{"level":"info","time":"2026-09-01T22:38:35Z","message":"closing PortainerDB"}

Start Portainer again and log in with the new random password b({aJ=)y@cU/9Z|H4lNi1FEG2eK85[06:
root@pi5:/# docker start portainer

References

Some articles I referenced when figuring this out were:
Reset the admin user’s password