It started happening on b1185 or b1240 (not sure which, but it never happened before MC 1.8), but I'm not sure what's causing it as it seemed to suddenly start happening. Might be an issue with my server, however what I don't get is that whenever that error starts appearing in the console, things stop working. Sign text stops loading, JSONAPI stops responding to queries properly (it logs the queries, but doesn't respond), LogBlock rollbacks stop working (they're queued but nothing happens), and sometimes chunks stop loading or mobs stop moving. What I'm basically wondering is whether anyone else has had this problem and know what causes it. It seems like some of Minecraft's and the plugins' threads are just dying based on how a lot of things simply stop working properly, however there are no errors in the console apart from "Can't keep up". Sometimes it starts happening an hour after a server restart, sometimes it takes a full day, but it consistently happens at least once per day. I usually have to restart the server every morning when I wake up or shortly thereafter. I'm posting my java parameters in case they're somehow related (though I doubt it as I've had those since 1.7.3, though I might have made one or two additions afterwards. Last modification was October 6th, 3 days after b1240 was released, so it might be related, however I didn't update to b1240 until 2 days after that). I believe what I added last was -XX:+UseBiasedLocking and -XX:+UseLargePages. However, UseLargePages causes a error about memory allocation on start, not sure if it's of any significance because the server still starts and runs properly at least for a while, so I kept it. I found most of the parameters in posts that explained what they did, and added only the ones I thought would be useful. Can't seem to find those posts again however. Code: java -server -Xincgc -Xmx6144M -Xms2048M -Xmn512M -XX:PermSize=128m -XX:MaxPermSize=256m -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+DisableExplicitGC -XX:+CMSIncrementalPacing -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -XX:+CMSParallelRemarkEnabled -XX:+AggressiveOpts -XX:MaxGCPauseMillis=50 -XX:-UseGCOverheadLimit -XX:+UseBiasedLocking -XX:+UseStringCache -XX:+UseCompressedStrings -XX:+OptimizeStringConcat -XX:+UseFastAccessorMethods -XX:+AggressiveOpts -XX:+UseLargePages -XX:UseSSE=3 -Djline.terminal=jline.UnsupportedTerminal -cp craftbukkit.jar org.bukkit.craftbukkit.Main Edit: It wasn't UseLargePages or UseBiasedLocking. Pretty sure it's not related to the java parameters.