[MC-75043] Invalid lang in options.txt leads to connection error

If your options.txt has under 'lang' an invalid language file, as an example, a language from a resource pack not in use anymore, it's not able to connect to any servers, with the generic error "java.io.IOException: An established connection was aborted by the software in your host machine" or just a "Disconnected" message.

Linked issues

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MC-111054 Invalid lang in options.txt leads to connection error Resolved

Comments 2

kumasasa 2015-11-10T23:23:46Z

Fixed between 1.8.2 and 15w45a.
Can connect to server with lang:xx_YZ without problems.

NOPEname 2016-12-01T12:41:23Z

I can confirm this bug for Minecraft 1.10.2 and 1.11.
The error "Disconnected" or "java.io.IOException: Eine vorhandene Verbindung wurde vom Remotehost geschlossen" (which should be the same as "java.io.IOException: An established connection was aborted by the software in your host machine") shows up every time I try to enter a server when a custom language file from a resourcepack is selected.