NextCloudPi Docker on Pi4: Unable to Activate

I suspect ncdata folder can not be created there.

Try:

sudo mkdir /mnt/usbdrive/ncdata
sudo chown www-data:www-data /mnt/usbdrive/ncdata
sudo docker rm nextcloudpi

docker run -p 4443:4443 -p 443:443 -p 80:80 -v /mnt/usbdrive/ncdata:/data --name nextcloudpi --restart unless-stopped ownyourbits/nextcloudpi-armhf:v1.24.0  ${IP}

and run,

docker logs -f nextcloudpi
wait for init done, (ctrl+c to exit log)

Also there is a detailed post on getting started with ncp docker

Can also check NCP’s documentation https://docs.nextcloudpi.com/en/how-to-get-started-with-ncp-docker/

Once your container is up and running you can copy old data, import database or run nc-scan, after copying files from previous ncdata.