Problem FTB Revelation crashing

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New Member
Dec 2, 2020
Whenever I try to start the mod pack, it will stop at 1/7 when loading, and give the error "The game crashed whilst initializing game
Error: java.lang.NoClassDefFoundError: scala/collection/Seq
Exit Code: -1"
If anyone can help me that would be much appreciated!


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Reactions: Littleterror198


New Member
Dec 7, 2020
Update: the altered java did remove the error. that alone has made me pause though. I originally started with java 8v271, and started receiving the error. i downgraded to what i hoped would be a more stable version, java 8v81. in all cases, the error was the same. i performed a full clean-up and removal of Minecraft, the FTB app and java, including all residual file prefs and data, and redownloaded the latest of each. i suspect that the original java i was running, java 8v271 potentially had been corrupted in some way. a simple re-install of java may work for anyone else with this issue.