MCreator suddenly not opening at all

Upvotes: 3
Issue description

For a few days now, I cannot open MCreator. I have tried uninstalling and reinstalling it, have tried the same with java and even have tried to open it as administrator, but it still refuses to open.Oh, I also use java 8. Can somebody help me please? (The photo below may help solving the problem)


Delete the file <user home>/.mcreator/preferences and run MCreator again.

Attachment Size
ERROR MESSAGE.png321.22 KB 321.22 KB

Issue comments

I suggest you to try to redownload and reinstall MCreator.

In this case, go to <user home/.mcreator/logs and paste the contents of the latest log file here.

019-07-09-16:12:37 [main/INFO] [Launcher] Starting MCreator 1.9.0, full version: 1.9.0
2019-07-09-16:12:37 [main/INFO] [Launcher] Java version: 1.8.0_212, specification: 1.8, VM name: LibericaJDK 64-Bit Server VM
2019-07-09-16:12:37 [main/INFO] [Launcher] Current JAVA_HOME for running instance: C:\Program Files\Pylo\MCreator\jdk\jre
2019-07-09-16:12:37 [main/ERROR] [Exception] Uncaught exception in main java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
    at$ ~[gson-2.8.5.jar:?]
    at ~[gson-2.8.5.jar:?]
    at ~[gson-2.8.5.jar:?]
    at ~[gson-2.8.5.jar:?]
    at ~[gson-2.8.5.jar:?]
    at net.mcreator.preferences.c.a(SourceFile:21) ~[mcreator.jar:?]
    at net.mcreator.Launcher.main(SourceFile:81) ~[mcreator.jar:?]
Caused by: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $
    at ~[gson-2.8.5.jar:?]
    at$ ~[gson-2.8.5.jar:?]
    ... 6 more

I need to do some testing to figure out why this happens.

Could one of the users that have this problem paste the contents of the file <user home>/.mcreator/preferences here?

The only files we can access are the ones in this form: <user home>/.mcreator/workspace/..etc..etc

How can we access the "preferences" type?

<user home (on Windows this folder is your username)>/.mcreator/ there is a file called preferences without any extensions next to some other files and folders such as gradle, logs, ...

Please someone with this issue, tell me the contents of this file. Without this data I can't really help on this issue.

Ok I finally found the file and I will reveal its contents here:

...(uuuh mine is empty)


Try to delete it (preferences file) and run MCreator again.

Ok, we'll try it once we can and let you know

  "general": {
    "compileOnSave": true,
    "notifyOfProgress": true,
    "checkUpdates": true
  "backups": {
    "workspaceAutosaveInterval": 30,
    "automatedBackupInterval": 5,
    "numberOfBackupsToStore": 10
  "ui": {
    "interfaceAccentColor": {
      "value": -7092917,
      "falpha": 0.0
    "aatext": true,
    "useSystemAAFontSettings": "on",
    "expandSectionsByDefault": false
  "blockly": {
    "enableComments": true,
    "enableCollapse": true,
    "enableTrashcan": true,
    "maxScale": 100,
    "minScale": 40,
    "scaleSpeed": 105,
    "legacyFont": false
  "ide": {
    "editorTheme": "MCreator",
    "autocomplete": true,
    "autocompleteMode": "Smart",
    "autocompleteDocWindow": true,
    "lineNumbers": true,
    "showErrorStrip": false
  "gradle": {
    "xms": 625,
    "xmx": 2048,
    "parallel": false,
    "offline": false,
    "java_home": {
      "path": ""
  "hidden": {
    "workspaceLargeIcons": true,
    "fullScreen": false,
    "projectTreeSplitPos": 0


after this the MCreator, has started! yey

YEEEES FINALLY!! THANK YOU! Your help is deepley appreciated!!!!

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