Absolutely no syntax highlighting

Check that Power Save mode is not enabled in the File menu and highlighting level for this file is not reduced (see the Hector icon at the bottom right of the status bar).

Hello Serge, thank you for answering.

I have already checked the Power Save mode and it is not enabled. The highlighting level is also on the highest possible value, so that shouldn't be a problem.

Also, I have tried invalidating caches & restarting.

Please share a sample project to reproduce the problem and the logs folder (https://intellij-support.jetbrains.com/hc/articles/207241085): https://intellij-support.jetbrains.com/hc/en-us/articles/206869619-Uploading-Large-Files-for-JetBrains-Support-Team.

As a wild guess - do you have "Carret Inspector" plugin enabled? It might destroy highlighting in editor.

I have created a very simple project and attached the logs here: https://cloud.jmnw.me/s/RF5KOS81W8a96ZF .

When searching for "Carret Inspector", I don't see any plugins coming up.

Disable .ignore plug-in: http://www.jetbrains.com/idea/webhelp/enabling-and-disabling-plugins.html.

PluginClassLoader[mobi.hsz.idea.gitignore, 1.5] 
java.lang.RuntimeException: java.lang.ClassNotFoundException: mobi.hsz.idea.gitignore.codeInspection.IgnoreCoverEntryInspection PluginClassLoader[mobi.hsz.idea.gitignore, 1.5]
 at com.intellij.codeInspection.InspectionEP.instantiateTool(InspectionEP.java:161)
 at com.intellij.codeInspection.ex.InspectionToolWrapper.getTool(InspectionToolWrapper.java:84)
 at com.intellij.codeInsight.daemon.impl.LocalInspectionsPass.getInspectionTools(LocalInspectionsPass.java:654)
 at com.intellij.codeInsight.daemon.impl.WholeFileLocalInspectionsPassFactory$2.getInspectionTools(WholeFileLocalInspectionsPassFactory.java:105)
 at com.intellij.codeInsight.daemon.impl.LocalInspectionsPass.collectInformationWithProgress(LocalInspectionsPass.java:136)
 at com.intellij.codeInsight.daemon.impl.ProgressableTextEditorHighlightingPass.doCollectInformation(ProgressableTextEditorHighlightingPass.java:82)
 at com.intellij.codeHighlighting.TextEditorHighlightingPass.collectInformation(TextEditorHighlightingPass.java:70)
 at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.b(PassExecutorService.java:434)
 at com.intellij.openapi.application.impl.ApplicationImpl.tryRunReadAction(ApplicationImpl.java:1026)
 at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.a(PassExecutorService.java:427)
 at com.intellij.openapi.progress.impl.CoreProgressManager.a(CoreProgressManager.java:494)
 at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:443)
 at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:54)
 at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.c(PassExecutorService.java:426)
 at com.intellij.codeInsight.daemon.impl.PassExecutorService$ScheduledPass.run(PassExecutorService.java:402)
 at com.intellij.concurrency.JobLauncherImpl$VoidForkJoinTask$1.exec(JobLauncherImpl.java:154)
 at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
 at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
 at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
 at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: java.lang.ClassNotFoundException: mobi.hsz.idea.gitignore.codeInspection.IgnoreCoverEntryInspection PluginClassLoader[mobi.hsz.idea.gitignore, 1.5]
 at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:64)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
 at java.lang.Class.forName0(Native Method)
 at java.lang.Class.forName(Class.java:348)
 at com.intellij.openapi.extensions.AbstractExtensionPointBean.findClass(AbstractExtensionPointBean.java:42)
 at com.intellij.openapi.extensions.AbstractExtensionPointBean.instantiate(AbstractExtensionPointBean.java:63)
 at com.intellij.codeInspection.InspectionEP.instantiateTool(InspectionEP.java:156)
 ... 19 more 

Thank you very much, it is working as intended now. I should have found that myself.

It surprises me that the .ignore plugin is broken since I am using it successfully on another machine. It may be an outdated version.

Have a good day!

Funnily enough, disabling this plugin also resolved this issue for me. You'd think it would be fixed by now with all the updates this one plugin gets