I also just had the same problem after I updated docker today. I tried the fix with the test image, but that did not work sad to say.
Privileged: on works
From webui
[19:54:47] [main/INFO]: Environment: authHost='https://authserver.mojang.com', accountsHost='https://api.mojang.com', sessionHost='https://sessionserver.mojang.com', servicesHost='https://api.minecraftservices.com', name='PROD' [19:54:47] [main/FATAL]: Failed to start the minecraft server java.lang.RuntimeException: java.nio.file.FileSystemException: .: Operation not permitted at cyg.<init>(SourceFile:98) ~[minecraft_server.jar:?] at cyg.a(SourceFile:105) ~[minecraft_server.jar:?] at net.minecraft.server.Main.main(SourceFile:117) [minecraft_server.jar:?] Caused by: java.nio.file.FileSystemException: .: Operation not permitted at sun.nio.fs.UnixException.translateToIOException(UnixException.java:91) ~[?:1.8.0_282] at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102) ~[?:1.8.0_282] at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107) ~[?:1.8.0_282] at sun.nio.fs.UnixPath.toRealPath(UnixPath.java:837) ~[?:1.8.0_282] at cyg.<init>(SourceFile:96) ~[minecraft_server.jar:?]
From log
2021-03-25 19:54:40.223872 [info] Host is running unRAID
2021-03-25 19:54:40.248044 [info] System information Linux de2d89c20da6 5.10.21-Unraid #1 SMP Sun Mar 7 13:39:02 PST 2021 x86_64 GNU/Linux
2021-03-25 19:54:40.275719 [info] OS_ARCH defined as 'x86-64'
2021-03-25 19:54:40.303176 [info] PUID defined as '99'
2021-03-25 19:54:40.362974 [info] PGID defined as '100'
2021-03-25 19:54:40.441762 [info] UMASK defined as '000'
2021-03-25 19:54:40.468391 [info] Permissions already set for volume mappings
2021-03-25 19:54:40.500737 [info] Deleting files in /tmp (non recursive)...
2021-03-25 19:54:40.528977 [info] CREATE_BACKUP_HOURS defined as '12'
2021-03-25 19:54:40.555569 [info] PURGE_BACKUP_DAYS defined as '14'
2021-03-25 19:54:40.582564 [info] ENABLE_WEBUI_CONSOLE defined as 'yes'
2021-03-25 19:54:40.609256 [info] ENABLE_WEBUI_AUTH defined as 'yes'
2021-03-25 19:54:40.635801 [info] WEBUI_USER defined as 'admin'
2021-03-25 19:54:40.662314 [info] WEBUI_PASS defined as 'poo'
2021-03-25 19:54:40.688913 [info] WEBUI_CONSOLE_TITLE defined as 'Minecraft Java'
2021-03-25 19:54:40.715721 [info] CUSTOM_JAR_PATH not defined,(via -e CUSTOM_JAR_PATH), defaulting to '/config/minecraft/minecraft_server.jar' (Mojang Minecraft Java)
2021-03-25 19:54:40.742199 [info] JAVA_VERSION not defined,(via -e JAVA_VERSION), defaulting to '8'
2021-03-25 19:54:40.772869 [info] JAVA_INITIAL_HEAP_SIZE defined as '1G'
2021-03-25 19:54:40.799393 [info] JAVA_MAX_HEAP_SIZE defined as '2G'
2021-03-25 19:54:40.826331 [info] JAVA_MAX_THREADS defined as '1'
2021-03-25 19:54:40.854474 [info] Starting Supervisor...
2021-03-25 19:54:41,092 INFO Included extra file "/etc/supervisor/conf.d/minecraft-server.conf" during parsing
2021-03-25 19:54:41,093 INFO Set uid to user 0 succeeded
2021-03-25 19:54:41,096 INFO supervisord started with pid 6
2021-03-25 19:54:42,098 INFO spawned: 'backup-script' with pid 127
2021-03-25 19:54:42,099 INFO spawned: 'purge-script' with pid 128
2021-03-25 19:54:42,101 INFO spawned: 'shutdown-script' with pid 129
2021-03-25 19:54:42,102 INFO spawned: 'start-script' with pid 130
2021-03-25 19:54:42,102 INFO reaped unknown pid 7 (exit status 0)
2021-03-25 19:54:42,106 DEBG 'purge-script' stdout output:
[info] Checking for old backups in 12 hours...
2021-03-25 19:54:42,106 INFO success: backup-script entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
2021-03-25 19:54:42,106 INFO success: purge-script entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
2021-03-25 19:54:42,106 INFO success: shutdown-script entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
2021-03-25 19:54:42,106 INFO success: start-script entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
2021-03-25 19:54:42,106 DEBG 'backup-script' stdout output:
[info] Waiting 12 hours before running worlds backup...
2021-03-25 19:54:42,108 DEBG 'start-script' stdout output:
[info] Minecraft folder '/config/minecraft' already exists, rsyncing newer files...
2021-03-25 19:54:42,155 DEBG 'start-script' stdout output:
[info] Checking EULA is set to 'true'...
2021-03-25 19:54:42,158 DEBG 'start-script' stdout output:
[info] EULA set to 'true'
2021-03-25 19:54:42,159 DEBG 'start-script' stdout output:
[info] Starting Minecraft Java process...
2021-03-25 19:54:42,162 DEBG 'start-script' stdout output:
[info] Minecraft Java process is running
2021-03-25 19:54:42,162 DEBG 'start-script' stdout output:
[info] Starting Minecraft console Web UI...
2021-03-25 19:54:42,171 DEBG 'start-script' stderr output:
2021/03/25 19:54:42 Permitting clients to write input to the PTY.
2021/03/25 19:54:42 Using Basic Authentication
2021/03/25 19:54:42 Server is starting with command: screen -x minecraft
2021-03-25 19:54:42,172 DEBG 'start-script' stderr output:
2021/03/25 19:54:42 URL: http://127.0.0.1:8222/
2021/03/25 19:54:42 URL: http://172.17.0.2:8222/
2021-03-25 19:54:47,676 DEBG 'start-script' stderr output:
2021/03/25 19:54:47 Basic Authentication Succeeded: 192.168.1.120:61534
2021/03/25 19:54:47 192.168.1.120:61534 200 GET /auth_token.js
2021-03-25 19:54:47,722 DEBG 'start-script' stderr output:
2021/03/25 19:54:47 New client connected: 192.168.1.120:61535
2021-03-25 19:54:47,726 DEBG 'start-script' stderr output:
2021/03/25 19:54:47 Command is running for client 192.168.1.120:61535 with PID 178 (args="-x minecraft"), connections: 1
2021/03/25 19:54:47 192.168.1.120:61535 101 GET /ws
2021-03-25 19:54:47,992 DEBG 'start-script' stderr output:
2021/03/25 19:54:47 Command exited for: 192.168.1.120:61535
2021-03-25 19:54:47,992 DEBG 'start-script' stderr output:
2021/03/25 19:54:47 Connection closed: 192.168.1.120:61535, connections: 0
2021/03/25 19:54:47 read tcp 172.17.0.2:8222->192.168.1.120:61535: use of closed network connection