Android Studio Start Failed - ClassNotFoundException: com.intellij.ide.plugins.PluginManager

Question

After installing Android Studio on a new Win8.1x64 machine, whenever I try to launch it I get a ClassNotFoundException: com.intellij.ide.plugins.PluginManager and Studio does not start. I have tried unzipping instead of installing, restarting the computer several times, cleaning all Android Studio related settings and files, still no result.

I have installed the latest JDK and the SDK. JAVA_HOME variable is set as well. Any idea what is going on? It's driving me nuts already. I would appreciate any help!

Here are the three different errors that randomly come up when I try to launch Android Studio.

java.lang.ClassNotFoundException: com.intellij.ide.plugins.PluginManager
at com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:148)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
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.ide.Bootstrap.main(Bootstrap.java:37)
at com.intellij.idea.Main.main(Main.java:84)

.

java.lang.NoClassDefFoundError: com/intellij/openapi/extensions/LogProvider
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at com.intellij.ide.Bootstrap.main(Bootstrap.java:37)
at com.intellij.idea.Main.main(Main.java:84)
Caused by: java.lang.ClassNotFoundException: com.intellij.openapi.extensions.LogProvider
at com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:148)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 4 more

.

java.lang.NoClassDefFoundError: com/intellij/openapi/extensions/PluginDescriptor
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
at java.lang.ClassLoader.defineClass(ClassLoader.java:642)
at com.intellij.util.lang.UrlClassLoader._defineClass(UrlClassLoader.java:195)
at com.intellij.util.lang.UrlClassLoader.defineClass(UrlClassLoader.java:191)
at com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:152)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
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.ide.Bootstrap.main(Bootstrap.java:37)
at com.intellij.idea.Main.main(Main.java:84)
Caused by: java.lang.ClassNotFoundException: com.intellij.openapi.extensions.PluginDescriptor
at com.intellij.util.lang.UrlClassLoader.findClass(UrlClassLoader.java:148)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 12 more

Answer 1

For anyone who has a similar problem, the errors were caused by antivirus software (in this case Avast). After uninstalling it I was able to normally install and start Android Studio. I'm not sure exactly what is happening between Avast and Android Studio, but this solved the problem.

Also, I installed Avast back and now I get multiple IllegalStateException s and NullPointerException s in the Android Studio Event Log, but these do not interfere with working in AS normally.