Help! MCreator new update not loading!

I get this problem too

Just reinstall it.

doesnt work

Go in your user folder (Users/User), then in .mcreator/logs. Finally, open the first file (mcreator.log I think), go paste the content of this file on pastebin and put the link here. We will be able to see the cause.

2020-04-24-08:21:12 [main/INFO] [Launcher] Starting MCreator 2020.2.14217 - 202000214217
2020-04-24-08:21:12 [main/INFO] [Launcher] Java version: 1.8.0_232, specification: 1.8, VM name: OpenJDK 64-Bit Server VM
2020-04-24-08:21:12 [main/INFO] [Launcher] Current JAVA_HOME for running instance: C:\Program Files\Pylo\MCreator\jdk\jre
2020-04-24-08:21:12 [main/DEBUG] [Preferences Manager] Loading preferences from C:\Users\Walter\.mcreator\preferences
2020-04-24-08:21:12 [main/INFO] [Launcher] Installation path: C:\Program Files\Pylo\MCreator
2020-04-24-08:21:12 [main/INFO] [Launcher] User home of MCreator: C:\Users\Walter\.mcreator\
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added stepsounds datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added damagesources datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added biomes datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added potions datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added biomedictionarytypes datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added mapcolors datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added achievements datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added particles datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added blocksitems datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added keybuttons datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added sounds datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added tabs datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added enhancements datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added entities datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added gamemodes datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/DEBUG] [Data List Loader] Added materials datamap to cache
2020-04-24-08:21:15 [AWT-EventQueue-0/INFO] [Plugin Loader] Loading plugin: core from .\plugins\mcreator-core.zip
2020-04-24-08:21:15 [AWT-EventQueue-0/INFO] [Plugin Loader] Loading plugin: generator-1.12.2 from .\plugins\generator-1.12.2.zip
2020-04-24-08:21:15 [AWT-EventQueue-0/INFO] [Plugin Loader] Loading plugin: generator-1.14.4 from .\plugins\generator-1.14.4.zip
2020-04-24-08:21:15 [AWT-EventQueue-0/INFO] [Plugin Loader] Loading plugin: generator-datapack-1.14.x from .\plugins\generator-datapack-1.14.x.zip
2020-04-24-08:21:15 [AWT-EventQueue-0/INFO] [Plugin Loader] Loading plugin: generator-datapack-1.15.x from .\plugins\generator-datapack-1.15.x.zip
2020-04-24-08:21:15 [AWT-EventQueue-0/INFO] [Application] Loading generator: 1.12.2/generator.yaml
2020-04-24-08:21:15 [AWT-EventQueue-0/ERROR] [Exception] Uncaught exception in AWT-EventQueue-0
java.lang.NoSuchFieldError: VERSION_2_3_29
    at net.mcreator.generator.template.a.d.<init>(SourceFile:16) ~[mcreator.jar:?]
    at net.mcreator.generator.template.d.<init>(SourceFile:16) ~[mcreator.jar:?]
    at net.mcreator.generator.c.<init>(SourceFile:56) ~[mcreator.jar:?]
    at net.mcreator.ui.g.<init>(SourceFile:100) ~[mcreator.jar:?]
    at net.mcreator.ui.g.b(SourceFile:167) ~[mcreator.jar:?]
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311) ~[?:1.8.0_232]
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758) ~[?:1.8.0_232]
    at java.awt.EventQueue.access$500(EventQueue.java:97) ~[?:1.8.0_232]
    at java.awt.EventQueue$3.run(EventQueue.java:709) ~[?:1.8.0_232]
    at java.awt.EventQueue$3.run(EventQueue.java:703) ~[?:1.8.0_232]
    at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_232]
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74) ~[?:1.8.0_232]
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728) ~[?:1.8.0_232]
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205) [?:1.8.0_232]
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) [?:1.8.0_232]
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) [?:1.8.0_232]
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [?:1.8.0_232]
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) [?:1.8.0_232]
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) [?:1.8.0_232]
 

Worked for me.