# Error on StartUp

**URL:** <https://discourse.processing.org/t/error-on-startup/17863>\
**Category:** Processing for Pi\
**Created:** [February 16, 2020, 3:54pm UTC](https://discourse.processing.org/t/error-on-startup/17863 "2020-02-16T15:54:11Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Alesk1969](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/alesk1969/32/8098_2.png) [@Alesk1969](https://discourse.processing.org/u/Alesk1969)\
**Post date:** [February 16, 2020, 3:54pm UTC](https://discourse.processing.org/t/error-on-startup/17863/1 "2020-02-16T15:54:11Z")

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Hi,

I just installed Processing on my PI 3B+ by running the instruction : “curl [https://processing.org/download/install-arm.sh](https://processing.org/download/install-arm.sh) | sudo sh” in the terminal. The installation went OK, I made a reboot, but when I’m trying to open Processing from the start menu, I have an error message " a serious error happened during Startup".  
Does anyone know what might be causing this issue ?

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**Author:** ![Alesk1969](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/alesk1969/32/8098_2.png) [@Alesk1969](https://discourse.processing.org/u/Alesk1969)\
**Post date:** [February 17, 2020, 8:03am UTC](https://discourse.processing.org/t/error-on-startup/17863/2 "2020-02-17T08:03:04Z")

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![erreur](https://canada1.discourse-cdn.com/flex036/uploads/processingfoundation1/original/2X/a/aae45fa3072b24ca2098b147582a26fd42ce9c35.png)

This is the error message I get when trying to open Processing from my PI.

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**Author:** ![jeremydouglass](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/jeremydouglass/32/20_2.png) [@jeremydouglass](https://discourse.processing.org/u/jeremydouglass)\
**Post date:** [February 19, 2020, 6:18pm UTC](https://discourse.processing.org/t/error-on-startup/17863/3 "2020-02-19T18:18:01Z")

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Your key error is:

> java.lang.ClassNotFoundException: processing.core.PApplet

This means the installation / configuration did not go well – core class of Processing is not found / not on the path. I’m not an expert in Processing for RaspberryPi, but you might want to try the entire installation over and pay careful attention to the installation log. Something is missing, in the wrong place, not on the path, or has bad permissions (e.g. from running under sudo, perhaps).

Hopefully people more experienced with RaspberryPi can chime in. Perhaps @kll ?

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**Author:** ![Alesk1969](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/alesk1969/32/8098_2.png) [@Alesk1969](https://discourse.processing.org/u/Alesk1969)\
**Post date:** [February 19, 2020, 8:21pm UTC](https://discourse.processing.org/t/error-on-startup/17863/4 "2020-02-19T20:21:11Z")

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Thank you for your answer! I’ll try again the install and check the installation log. I haven’t done yet the last Raspbian update. Maybe this error has something to do with it …?