For those having issues with game.prefs and character encoding problems an alpha client has been released at https://github.com/FAForever/downlords-faf-client/releases/tag/v2023.2.0-alpha-1 Which you can try which should fix the problem.
Client java.lang.error fix
Please, can you give feedback if it fixes your issue with the malformed exception you encountered for "Game.prefs":
Пожалуйста, дайте обратную связь, если это исправит вашу проблему с неправильно сформированным исключением, с которым вы столкнулись для "Game.prefs":
(users who had issues with it)
@eb_ @broodlow @hero_swe @goshawk_27 @the_dark_archon @custos_stsp @dewostator23 @xumuk_911 @rodi @tvelv @amish @iku-turso @n_a_g @opankist @serfed @crimsontyrant @xathos @Glotarj @Empty_exe @Hellpers @FerGanec @xXMadnessXx13 @itstehendz @Scionos @Tatankasapa
@magge I played solo 5 skating rinks and with a friend a couple on alpha, there were no problems with java
@magge Gave me a couple of errors when logging in (which I was unable to copy) but after getting in all worked great. So thank you for the help.
Having issues joining custom games :-
Client Version: 2023.1.2
java.lang.Error: java.nio.charset.MalformedInputException: Input length = 1
at java.base/java.lang.String.decodeWithDecoder(String.java:1212)
at java.base/java.lang.String.newStringNoRepl1(String.java:786)
at java.base/java.lang.String.newStringNoRepl(String.java:738)
at java.base/java.lang.System$2.newStringNoRepl(System.java:2390)
at java.base/java.nio.file.Files.readString(Files.java:3369)
at com.faforever.client.mod.ModService.readPreferencesFile(ModService.java:313)
at com.faforever.client.mod.ModService.readActiveMods(ModService.java:329)
at com.faforever.client.mod.ModService.enableSimMods(ModService.java:231)
The alpha client resolved the issue, however it reset all settings and blueprints.