To do that pm2 flush
Then start again

pi@raspberrypi:~/MagicMirror/modules $ cat /home/pi/.npm/_logs/2020-04-10T02_27_39_057Z-debug.log
0 info it worked if it ends with ok
1 verbose cli [ '/usr/bin/node', '/usr/local/bin/npm', 'start' ]
2 info using npm@6.14.4
3 info using node@v10.15.2
4 verbose run-script [ 'prestart', 'start', 'poststart' ]
5 info lifecycle magicmirror@2.11.0~prestart: magicmirror@2.11.0
6 info lifecycle magicmirror@2.11.0~start: magicmirror@2.11.0
7 verbose lifecycle magicmirror@2.11.0~start: unsafe-perm in lifecycle true
8 verbose lifecycle magicmirror@2.11.0~start: PATH: /usr/local/lib/node_modules/npm/node_modules/npm-lifecycle/node-gyp-bin:/home/pi/MagicMirror/node_modules/.bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games
9 verbose lifecycle magicmirror@2.11.0~start: CWD: /home/pi/MagicMirror
10 silly lifecycle magicmirror@2.11.0~start: Args: [ '-c',
10 silly lifecycle   'DISPLAY="${DISPLAY:=:0}" ./node_modules/.bin/electron js/electron.js' ]
11 silly lifecycle magicmirror@2.11.0~start: Returned: code: 1  signal: null
12 info lifecycle magicmirror@2.11.0~start: Failed to exec start script
13 verbose stack Error: magicmirror@2.11.0 start: `DISPLAY="${DISPLAY:=:0}" ./node_modules/.bin/electron js/electron.js`
13 verbose stack Exit status 1
13 verbose stack     at EventEmitter.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-lifecycle/index.js:332:16)
13 verbose stack     at EventEmitter.emit (events.js:189:13)
13 verbose stack     at ChildProcess.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-lifecycle/lib/spawn.js:55:14)
13 verbose stack     at ChildProcess.emit (events.js:189:13)
13 verbose stack     at maybeClose (internal/child_process.js:970:16)
13 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:259:5)
14 verbose pkgid magicmirror@2.11.0
15 verbose cwd /home/pi/MagicMirror
16 verbose Linux 4.19.97-v7+
17 verbose argv "/usr/bin/node" "/usr/local/bin/npm" "start"
18 verbose node v10.15.2
19 verbose npm  v6.14.4
20 error code ELIFECYCLE
21 error errno 1
22 error magicmirror@2.11.0 start: `DISPLAY="${DISPLAY:=:0}" ./node_modules/.bin/electron js/electron.js`
22 error Exit status 1
23 error Failed at the magicmirror@2.11.0 start script.
23 error This is probably not a problem with npm. There is likely additional logging output above.
24 verbose exit [ 1, true ]
pi@raspberrypi:~/MagicMirror/modules $

let us know how it goes

@sdetweil, I’ll be trying your install script and update script from now on. Hopefully it will be a smoother experience that usual.

This is why I’ve never built a MagicMirror as a gift. I can barely maintain my own mirror.

in addition to what @Stoffbeuteluwe posted, I suggest you use my updater script from
https://github.com/sdetweil/MagicMirror_scripts

upgrade-script.sh will do the git pull and npm install, and refresh npm setup for any modules that might need it
it should handle all the work… and give you a trial run of all that…

only applying changes if u request them

give it a try this works on Mac as well

bash -c "$(curl -sL https://raw.githubusercontent.com/sdetweil/MagicMirror_scripts/master/upgrade-script.sh)"

no changes are made to the local repo or the working copy

if you WANT to actually apply the changes do

bash -c "$(curl -sL https://raw.githubusercontent.com/sdetweil/MagicMirror_scripts/master/upgrade-script.sh)" apply

if you have already done the git pull, you will need to use force to get the script update the same version

bash -c "$(curl -sL https://raw.githubusercontent.com/sdetweil/MagicMirror_scripts/master/upgrade-script.sh)" force

there is a log file (upgrade.log) in the MagicMirror/installers folder…