Update: solved the problem by using your solution here: https://forum.magicmirror.builders/topic/13770/2-13-calendar-fix-for-office-365-users but I don’t have a Office 365-account.
Thanks for the solution!!

Ok, so maybe I had something running in the background that I couldn’t see. When I ran npm start dev I got this error instead:

[2020-12-30 22:53:03.906] [ERROR]  Whoops! There was an uncaught exception...
[2020-12-30 22:53:03.908] [ERROR]  TypeError: Cannot read property 'iana' of undefined
    at getIanaTZFromMS (/home/pi/MagicMirror/node_modules/node-ical/ical.js:108:30)
    at /home/pi/MagicMirror/node_modules/node-ical/ical.js:175:23
    at Object.DTSTART (/home/pi/MagicMirror/node_modules/node-ical/ical.js:457:32)
    at Object.handleObject (/home/pi/MagicMirror/node_modules/node-ical/ical.js:483:39)
    at Object.parseLines (/home/pi/MagicMirror/node_modules/node-ical/ical.js:534:18)
    at Object.parseICS (/home/pi/MagicMirror/node_modules/node-ical/ical.js:590:18)
    at Object.sync.parseICS (/home/pi/MagicMirror/node_modules/node-ical/node-ical.js:190:15)
    at Object.autodetect.parseICS (/home/pi/MagicMirror/node_modules/node-ical/node-ical.js:221:17)
    at Request._callback (/home/pi/MagicMirror/modules/default/calendar/calendarfetcher.js:79:22)
    at Request.self.callback (/home/pi/MagicMirror/node_modules/request/request.js:185:22)

@sdetweil thanks! but it only seems like I have one instance running because now nothing is running.

Hi!
I have problem with one of my calendars that wont show events. The problem started when updating to v2.13.0 and the calendar module caused the mirror to only show a blank screen. I solved it by outcomment the module and haven’t had time to dig into it for months until now.
The problem back then I think was that I had changed the calendar names, so the url’s were wrong, so now I have solved it to show two calendars, but cannot see the last calendar’s event. I have tripple checked the ical-address, so that’s not the problem now. I have also gone through this link: https://github.com/MichMich/MagicMirror/issues/839 and tried to see if I got the same problem by run npm start dev but I wont get the same error message. This is my error message:

> magicmirror@2.13.0 start /home/pi/MagicMirror
> DISPLAY="${DISPLAY:=:0}" ./node_modules/.bin/electron js/electron.js "dev"

/home/pi/MagicMirror/node_modules/electron/dist/electron: /lib/arm-linux-gnueabihf/libdbus-1.so.3: no version information available (required by /home/pi/MagicMirror/node_modules/electron/dist/electron)
/home/pi/MagicMirror/node_modules/electron/dist/electron: /lib/arm-linux-gnueabihf/libdbus-1.so.3: no version information available (required by /home/pi/MagicMirror/node_modules/electron/dist/electron)
[2020-12-30 22:08:23.415] [LOG]    Starting MagicMirror: v2.13.0
[2020-12-30 22:08:23.433] [LOG]    Loading config ...
[2020-12-30 22:08:23.447] [LOG]    Loading module helpers ...
[2020-12-30 22:08:23.451] [LOG]    No helper found for module: alert.
[2020-12-30 22:08:23.556] [LOG]    Initializing new module helper ...
[2020-12-30 22:08:23.558] [LOG]    Module helper loaded: updatenotification
[2020-12-30 22:08:23.564] [LOG]    Initializing new module helper ...
[2020-12-30 22:08:23.567] [LOG]    Module helper loaded: mmm-systemtemperature
[2020-12-30 22:08:23.570] [LOG]    No helper found for module: clock.
[2020-12-30 22:08:24.566] [LOG]    Initializing new module helper ...
[2020-12-30 22:08:24.569] [LOG]    Module helper loaded: calendar
[2020-12-30 22:08:24.677] [LOG]    Initializing new module helper ...
[2020-12-30 22:08:24.678] [LOG]    Module helper loaded: MMM-YrThen
[2020-12-30 22:08:25.787] [LOG]    Initializing new module helper ...
[2020-12-30 22:08:25.789] [LOG]    Module helper loaded: mmm-weatherchart
[2020-12-30 22:08:25.844] [LOG]    Initializing new module helper ...
[2020-12-30 22:08:25.845] [LOG]    Module helper loaded: newsfeed
[2020-12-30 22:08:25.846] [LOG]    All module helpers loaded.
[2020-12-30 22:08:26.086] [LOG]    Starting server on port 8080 ...
[2020-12-30 22:08:26.114] [LOG]    Server started ...
[2020-12-30 22:08:26.116] [LOG]    Connecting socket for: updatenotification
[2020-12-30 22:08:26.118] [LOG]    Connecting socket for: mmm-systemtemperature
[2020-12-30 22:08:26.119] [LOG]    Starting node helper: mmm-systemtemperature
[2020-12-30 22:08:26.120] [LOG]    Connecting socket for: calendar
[2020-12-30 22:08:26.121] [LOG]    Starting node helper for: calendar
[2020-12-30 22:08:26.122] [LOG]    Connecting socket for: MMM-YrThen
[2020-12-30 22:08:26.124] [LOG]    MMM-YrThen 12/30/2020 10:08:26 PM: Starting helper for MMM-YrThen
[2020-12-30 22:08:26.125] [LOG]    Connecting socket for: mmm-weatherchart
[2020-12-30 22:08:26.126] [LOG]    Starting node helper: mmm-weatherchart
[2020-12-30 22:08:26.129] [LOG]    Connecting socket for: newsfeed
[2020-12-30 22:08:26.131] [LOG]    Starting node helper for: newsfeed
[2020-12-30 22:08:26.133] [LOG]    Sockets connected & modules started ...
Fontconfig warning: "/etc/fonts/fonts.conf", line 86: unknown element "blank"
[2020-12-30 22:08:26.336] [ERROR]  Whoops! There was an uncaught exception...
[2020-12-30 22:08:26.341] [ERROR]  Error: listen EADDRINUSE: address already in use 127.0.0.1:8080
    at Server.setupListenHandle [as _listen2] (net.js:1226:14)
    at listenInCluster (net.js:1274:12)
    at GetAddrInfoReqWrap.doListen [as callback] (net.js:1413:7)
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:65:10) {
  code: 'EADDRINUSE',
  errno: 'EADDRINUSE',
  syscall: 'listen',
  address: '127.0.0.1',
  port: 8080
}
[2020-12-30 22:08:26.363] [ERROR]  MagicMirror will not quit, but it might be a good idea to check why this happened. Maybe no internet connection?
[2020-12-30 22:08:26.366] [ERROR]  If you think this really is an issue, please open an issue on GitHub: https://github.com/MichMich/MagicMirror/issues
[2020-12-30 22:08:26.380] [LOG]    Launching application.

I have also checked the ical.js solution, but I don’t know how to solve it, because I only have a folder with that name and cannot create a file.
I don’t have a lot of programming knowledges so please kind answers :)

@evroom got an error on the egrep command:

pi@raspberrypi:~ $ cat /proc/device-tree/model
Raspberry Pi 3 Model B Rev 1.2pi@raspberrypi:~ $ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 8.0 (jessie)
Release:        8.0
Codename:       jessie
pi@raspberrypi:~ $ npm --version
5.6.0
pi@raspberrypi:~ $ node --version
v9.11.2
pi@raspberrypi:~ $ pm2 --version
3.5.1
pi@raspberrypi:~ $ cat /boot/config.txt | egrep -v '^$|^#|^['
grep: Invalid regular expression

@evroom actually no errors like I got before…

PM2        | 2019-08-29T21:46:00: PM2 log: pid=1331 msg=failed to kill - retrying in 100ms
PM2        | 2019-08-29T21:46:00: PM2 log: App [mm:0] exited with code [0] via signal [SIGINT]
PM2        | 2019-08-29T21:46:00: PM2 log: pid=1331 msg=process killed
PM2        | 2019-08-29T21:46:00: PM2 log: App [mm:0] starting in -fork mode-
PM2        | 2019-08-29T21:46:00: PM2 log: App [mm:0] online

/home/pi/.pm2/logs/mm-out.log last 100 lines:
0|mm       | Shutting down server...
0|mm       | Stopping module helper: updatenotification
0|mm       | Stopping module helper: mmm-systemtemperature
0|mm       |
0|mm       | > magicmirror@2.8.0 start /home/pi/MagicMirror
0|mm       | > sh run-start.sh
0|mm       |
0|mm       | Starting MagicMirror: v2.8.0
0|mm       | Loading config ...
0|mm       | Loading module helpers ...
0|mm       | No helper found for module: alert.
0|mm       | Initializing new module helper ...
0|mm       | Module helper loaded: updatenotification
0|mm       | Initializing new module helper ...
0|mm       | Module helper loaded: mmm-systemtemperature
0|mm       | No helper found for module: clock.
0|mm       | Initializing new module helper ...
0|mm       | Module helper loaded: calendar
0|mm       | Initializing new module helper ...
0|mm       | Module helper loaded: MMM-YrThen
0|mm       | Initializing new module helper ...
0|mm       | Module helper loaded: mmm-weatherchart
0|mm       | Initializing new module helper ...
0|mm       | Module helper loaded: newsfeed
0|mm       | All module helpers loaded.
0|mm       | Starting server on port 8080 ...
0|mm       | Server started ...
0|mm       | Connecting socket for: updatenotification
0|mm       | Connecting socket for: mmm-systemtemperature
0|mm       | Starting node helper: mmm-systemtemperature
0|mm       | Connecting socket for: calendar
0|mm       | Starting node helper for: calendar
0|mm       | Connecting socket for: MMM-YrThen
0|mm       | MMM-YrThen 8/29/2019 9:46:08 PM: Starting helper for MMM-YrThen
0|mm       | Connecting socket for: mmm-weatherchart
0|mm       | Starting node helper: mmm-weatherchart
0|mm       | Connecting socket for: newsfeed
0|mm       | Starting module: newsfeed
0|mm       | Sockets connected & modules started ...
0|mm       | Launching application.

/home/pi/.pm2/logs/mm-error.log last 100 lines:
0|mm       | /home/pi/MagicMirror/node_modules/electron/dist/electron: /lib/arm-linux-gnueabihf/libdbus-1.so.3: no version information available (required by /home/pi/MagicMirror/node_modules/electron/dist/electron)
0|mm       | /home/pi/MagicMirror/node_modules/electron/dist/electron: /lib/arm-linux-gnueabihf/libdbus-1.so.3: no version information available (required by /home/pi/MagicMirror/node_modules/electron/dist/electron)
0|mm       | (node:2465) [DEP0025] DeprecationWarning: sys is deprecated. Use util instead.
0|mm       | /proc/self/exe: /lib/arm-linux-gnueabihf/libdbus-1.so.3: no version information available (required by /proc/self/exe)
0|mm       | ATTENTION: default value of option force_s3tc_enable overridden by environment.

I really appreciate you want to look into my errors, I’m not too good on this :)

And of course it didn’t work now when I tried to switch back to default calendar module and then back to the other calendar module…

@evroom I sat right now and installed a new calendar module and suddenly the mmm-weatherchart started working… :thinking_face:

Did the $ pm2 logs --lines 100 and got a lot of errors, but I guess because everything’s working fine so don’t have to bother right now?!

@sdetweil Thanks! This worked for me as it doesn’t kill it anymore. Hope for a quick fix. Can I follow the process somewhere?

Just to be clear, I’m a girl… ;)
The module worked as a charm before the update. So you think I should just skip the apostrophe on the updateInterval and hideBorder?

Hi,
After updated to 2.8.0 I have trouble with a blank screen. I comment out every module one at a time and found out that mmm-weatherchart was the problem. Is there something wrong in my code?

{
		module: 'mmm-weatherchart',
		position: 'bottom_left',
		config: {
			country: 'Sweden',
			area: 'Halland',
			city: 'Stråvalla',
			updateInterval: '3600000',
			hideBorder: 'true'
			}
},

Everything works after setting maximumEntries after each URL. I don’t like it though because it doesn’t show the 10 upcoming items due to where the items are in time. But guess I have to live with it :)

@gripworks I’ve already tried this and unfortunately it didn’t work for me with two calendars :(

I have this problem too! Someone who has a suggestion on how to solve this problem?

Same here too with two calendars. Tried to set max entries to 5, but didn’t work for me, have at least 20 entries as I can see.