# Java.lang errors on running a sketch – new installs on Windows

**URL:** <https://discourse.processing.org/t/java-lang-errors-on-running-a-sketch-new-installs-on-windows/36112>\
**Category:** Processing\
**Created:** [April 4, 2022, 6:37am UTC](https://discourse.processing.org/t/java-lang-errors-on-running-a-sketch-new-installs-on-windows/36112 "2022-04-04T06:37:43Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kevinschlei](https://avatars.discourse-cdn.com/v4/letter/k/77aa72/32.png) [@kevinschlei](https://discourse.processing.org/u/kevinschlei)\
**Post date:** [April 4, 2022, 6:37am UTC](https://discourse.processing.org/t/java-lang-errors-on-running-a-sketch-new-installs-on-windows/36112/1 "2022-04-04T06:37:44Z")

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I have a few students with fresh installs of Processing 4b7, 4b6, and even 3.5.4 that are getting the following error when trying to run a new blank sketch:

```auto
java.lang.RuntimeException: java.lang.ClassNotFoundException: sketch_220404a
 at processing.core.PApplet.runSketch(PApplet.java:10397)
 at processing.core.PApplet.main(PApplet.java:10187)
Caused by: java.lang.ClassNotFoundException: sketch_220404a
 at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
 at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
 at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
 at processing.core.PApplet.runSketch(PApplet.java:10390)
 ... 1 more
RuntimeException: java.lang.ClassNotFoundException: sketch_220404a

```

I thought maybe they were trying to run from inside a .zip file, but no. One of them is on Windows 11, the other on Windows 10.

I can’t quite figure this out. Are they missing a separate Java install somewhere? Is it a permissions thing? Any leads would be appreciated.

---

<div class="post-metadata">

**Author:** ![kevinschlei](https://avatars.discourse-cdn.com/v4/letter/k/77aa72/32.png) [@kevinschlei](https://discourse.processing.org/u/kevinschlei)\
**Post date:** [April 4, 2022, 11:42pm UTC](https://discourse.processing.org/t/java-lang-errors-on-running-a-sketch-new-installs-on-windows/36112/2 "2022-04-04T23:42:13Z")

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Okay, seemed to have figured it out. The Processing app needed to be run as administrator. Setting that option fixed the issue.