(urgent!) cant do backup - Nextcloud(pi) isnt running - What to do?

(Urgent) cant do anything nextcloudpi (backup, config, update)!

Today I wanted to make a manual backup (worked a few days ago fine) to update to v1.9.3 afterwards.

But When I click apply in the web panel or with ssh I am getting the same error. I am afraid I cant backup my data anymore - anyone a Idea?? I am getting also this error when I try to update the apps or when I want to make a btrfs-snapshot?

[ nc-backup ]

PHP Fatal error: Interface ‘OCA\Files_External\Lib\Config\IBackendProvider’ not found in /var/www/nextcloud/apps/files_external_gdrive/lib/AppInfo/Application.php on line 32
Error reading data directory. Is NextCloud running and configured?

My System Status/Information:

sudo ncp-report
NextCloudPi diagnostics

PHP Fatal error:  Interface 'OCA\Files_External\Lib\Config\IBackendProvider' not found in /var/www/nextcloud/apps/files_external_gdrive/lib/AppInfo/Application.php on line 32
NextCloudPi version  v1.8.0
NextCloudPi image    NextCloudPi_01-14-19
distribution         Raspbian GNU/Linux 9 \n \l
automount            yes
USB devices          sda
datadir              /media/USBdrive/ncdata
data in SD           no
data filesystem      btrfs
data disk usage      447G/2.8T
rootfs usage         2.3G/30G
swapfile             /var/swap
dbdir                /var/lib/mysql
Nextcloud check      error
HTTPD service        up
PHP service          up
MariaDB service      up
Redis service        up
Postfix service      up
internet check       ok
port check 80        open
port check 443       open
IP                   ***REMOVED SENSITIVE VALUE***
gateway              ***REMOVED SENSITIVE VALUE***
interface            eth0
certificates         ***REMOVED SENSITIVE VALUE***
NAT loopback         no
uptime               26min

Nextcloud configuration

PHP Fatal error:  Interface 'OCA\Files_External\Lib\Config\IBackendProvider' not found in /var/www/nextcloud/apps/files_external_gdrive/lib/AppInfo/Application.php on line 32

HTTPd logs

[Tue Mar 12 06:25:03.325384 2019] [ssl:warn] [pid 919:tid 1995407600] AH01909: localhost:4443:0 server certificate does NOT include an ID which matches the server name
[Tue Mar 12 06:25:04.001088 2019] [mpm_event:notice] [pid 919:tid 1995407600] AH00489: Apache/2.4.25 (Raspbian) OpenSSL/1.0.2r configured -- resuming normal operations
[Tue Mar 12 06:25:04.001221 2019] [core:notice] [pid 919:tid 1995407600] AH00094: Command line: '/usr/sbin/apache2'
[Tue Mar 12 15:51:45.944571 2019] [proxy_fcgi:error] [pid 6177:tid 1774355504] [client 192.168.178.34:49278] AH01071: Got error 'PHP message: PHP Notice:  Undefined index: app in /var/www/ncp-web/index.php on line 214\n'
[Tue Mar 12 16:13:35.823920 2019] [proxy_fcgi:error] [pid 6177:tid 1875067952] [client 192.168.178.34:49280] AH01067: Failed to read FastCGI header
[Tue Mar 12 16:13:35.824152 2019] [proxy_fcgi:error] [pid 6177:tid 1875067952] (104)Connection reset by peer: [client 192.168.178.34:49280] AH01075: Error dispatching request to :4443:
[Tue Mar 12 16:13:35.923450 2019] [mpm_event:notice] [pid 919:tid 1995407600] AH00491: caught SIGTERM, shutting down
[Tue Mar 12 16:13:48.559856 2019] [ssl:warn] [pid 647:tid 1995878640] AH01909: localhost:4443:0 server certificate does NOT include an ID which matches the server name
[Tue Mar 12 16:13:49.049278 2019] [ssl:warn] [pid 919:tid 1995878640] AH01909: localhost:4443:0 server certificate does NOT include an ID which matches the server name
[Tue Mar 12 16:13:50.010405 2019] [mpm_event:notice] [pid 919:tid 1995878640] AH00489: Apache/2.4.25 (Raspbian) OpenSSL/1.0.2r configured -- resuming normal operations
[Tue Mar 12 16:13:50.010591 2019] [core:notice] [pid 919:tid 1995878640] AH00094: Command line: '/usr/sbin/apache2'

Database logs

2019-03-12 16:14:38 1995714352 [Note] InnoDB: innodb_empty_free_list_algorithm has been changed to legacy because of small buffer pool size. In order to use backoff, increase buffer pool at least up to 20MB.

2019-03-12 16:14:38 1995714352 [Note] InnoDB: Using mutexes to ref count buffer pool pages
2019-03-12 16:14:38 1995714352 [Note] InnoDB: The InnoDB memory heap is disabled
2019-03-12 16:14:38 1995714352 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2019-03-12 16:14:38 1995714352 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
2019-03-12 16:14:38 1995714352 [Note] InnoDB: Compressed tables use zlib 1.2.8
2019-03-12 16:14:38 1995714352 [Note] InnoDB: Using Linux native AIO
2019-03-12 16:14:38 1995714352 [Note] InnoDB: Using generic crc32 instructions
2019-03-12 16:14:38 1995714352 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2019-03-12 16:14:38 1995714352 [Note] InnoDB: Completed initialization of buffer pool
2019-03-12 16:14:39 1995714352 [Note] InnoDB: Highest supported file format is Barracuda.
2019-03-12 16:14:39 1995714352 [Note] InnoDB: 128 rollback segment(s) are active.
2019-03-12 16:14:39 1995714352 [Note] InnoDB: Waiting for purge to start
2019-03-12 16:14:39 1995714352 [Note] InnoDB:  Percona XtraDB (http://www.percona.com) 5.6.41-84.1 started; log sequence number 974598049
2019-03-12 16:14:39 1379922752 [Note] InnoDB: Dumping buffer pool(s) not yet started
2019-03-12 16:14:39 1995714352 [Note] Plugin 'FEEDBACK' is disabled.
2019-03-12 16:14:39 1995714352 [Note] Server socket created on IP: '127.0.0.1'.
2019-03-12 16:14:39 1995714352 [Note] /usr/sbin/mysqld: ready for connections.
Version: '10.1.37-MariaDB-0+deb9u1'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  Raspbian 9.0

Nextcloud logs

{"reqId":"P79mkAlBudottjzt1BQD","level":3,"time":"2019-03-12T16:39:14+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"XIfgtH8AAQEAAAPyWnwAAABJ","level":3,"time":"2019-03-12T16:39:16+00:00","remoteAddr":"92.117.115.216","user":"Friedemann","app":"PHP","method":"GET","url":"\/ocs\/v2.php\/apps\/notifications\/api\/v2\/notifications?format=json","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"Mozilla\/5.0 (Windows) mirall\/2.5.1final (build 20181204) (Nextcloud)","version":"15.0.4.0"}
{"reqId":"LufunIHsXRFULEK8nMaH","level":3,"time":"2019-03-12T16:39:17+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"ruDj7zpcV3dTbo8AEIEs","level":3,"time":"2019-03-12T16:39:25+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"Hjc7JMsjXQsZkKPxp1TU","level":3,"time":"2019-03-12T16:39:28+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"fWUo40xYW9USyTg94QcO","level":3,"time":"2019-03-12T16:39:36+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"Kld7uSJrf7OPushG9oOP","level":3,"time":"2019-03-12T16:39:38+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"XIfgzX8AAQEAAAPyWn8AAABL","level":3,"time":"2019-03-12T16:39:41+00:00","remoteAddr":"92.117.115.216","user":"Charlotte","app":"PHP","method":"GET","url":"\/ocs\/v2.php\/core\/navigation\/apps?absolute=true&format=json","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"Mozilla\/5.0 (Macintosh) mirall\/2.5.1final (build 20181204) (Nextcloud)","version":"15.0.4.0"}
{"reqId":"LDsqlapkdEMelgHp2fiK","level":3,"time":"2019-03-12T16:39:46+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"ySRZxCPb7XM59jU6gNnQ","level":3,"time":"2019-03-12T16:39:49+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"3j9fUjR0hUHwJGOUFd2e","level":3,"time":"2019-03-12T16:39:57+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"XIfg3H8AAQEAAAPyWoEAAABN","level":3,"time":"2019-03-12T16:39:58+00:00","remoteAddr":"92.117.115.216","user":"Friedemann","app":"PHP","method":"GET","url":"\/index.php\/204","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"Mozilla\/5.0 (Android) ownCloud-android\/3.5.1 RC2","version":"15.0.4.0"}
{"reqId":"gSAXWbfVfkdLRNEhWPuZ","level":3,"time":"2019-03-12T16:39:59+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"Fx3bv8mZ2s0tfg6PrphU","level":3,"time":"2019-03-12T16:40:04+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"XIfg438AAQEAAAPyWoIAAABO","level":3,"time":"2019-03-12T16:40:05+00:00","remoteAddr":"92.117.115.216","user":"Friedemann","app":"PHP","method":"GET","url":"\/index.php\/204","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"Mozilla\/5.0 (Android) ownCloud-android\/3.5.1 RC2","version":"15.0.4.0"}
{"reqId":"q2E8Os7A6bI1XH60hMI0","level":3,"time":"2019-03-12T16:40:07+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"K2B06preAagccJlHjurq","level":3,"time":"2019-03-12T16:40:09+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"HKqxDEenPZHrcG1PnToz","level":3,"time":"2019-03-12T16:40:09+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}
{"reqId":"XIfg638AAQEAAAPyWoQAAABR","level":3,"time":"2019-03-12T16:40:11+00:00","remoteAddr":"92.117.115.216","user":"Charlotte","app":"PHP","method":"GET","url":"\/ocs\/v2.php\/core\/navigation\/apps?absolute=true&format=json","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"Mozilla\/5.0 (Macintosh) mirall\/2.5.1final (build 20181204) (Nextcloud)","version":"15.0.4.0"}
{"reqId":"YmCJqVBUPDZdPepaFsjX","level":3,"time":"2019-03-12T16:40:15+00:00","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/files_external_gdrive\/lib\/AppInfo\/Application.php#32","userAgent":"--","version":"15.0.4.0"}

I am concerned about "Nextcloud check - error"

(I already rebooted the system, but it didnt change the error message)

How can I get my Nextcloud back running without error??

I really have panic at the moment…

Anyone an Idea?

I dont now how I fix it but I think the importatn point of my action was following:

After reading the logs carefully I noticed, that the App storage_external_gdrive the problems made. So I (am just a beginner) navigated to my apps folder and moved it to another location (I thought just try it.)

something like this:

sudo -i

mv /var/www/nextcloud/apps/storage_external_gdriver /media/myharddrive/somefolder/storage_external_gdrive 

after this I tried again to make a backup, got alot of other error messages. (I cant remember exactly but I think I rebooted and copied the folder back, ant then the Nextfcloud service was running again, and I was able to make the backup.