# NAT0400 Invalid library ID

**URL:** <https://techcommunity.softwareag.com/t/nat0400-invalid-library-id/196513>\
**Category:** Forum\
**Tags:** Adabas-Natural, Natural, NaturalONE, Adabas-Natural-Community-Edition, Natural-on-Windows-Unix\
**Created:** [September 20, 2017, 4:55pm UTC](https://techcommunity.softwareag.com/t/nat0400-invalid-library-id/196513 "2017-09-20T16:55:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sebastiao\_da\_Paz\_Lima](https://avatars.discourse-cdn.com/v4/letter/s/c0e974/32.png) [@Sebastiao\_da\_Paz\_Lima](https://techcommunity.softwareag.com/u/Sebastiao_da_Paz_Lima)\
**Post date:** [September 20, 2017, 4:55pm UTC](https://techcommunity.softwareag.com/t/nat0400-invalid-library-id/196513/1 "2017-09-20T16:55:15Z")

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Hi everyone,  
I installed NaturalONE Community Edition on my windows 7 machine, started testing the application  
Hello World application and I am getting the following errors: "Unable to Register Main Window Class and connection to localhost failed Reason: LOGON 4760 NAT0400 Invalid library ID.

What should I do?

 ![TelaNaturalONE.png](https://global.discourse-cdn.com/techcommunity/original/2X/0/04b0237bf12d1d1e67ab789bcdb72df4c65fd6da.png)

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<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/techcommunity/original/3X/c/d/cd19967bb605d28a72d77eb83a1cae22f3df2eb8.svg) [@system](https://techcommunity.softwareag.com/u/system)\
**Post date:** [April 2, 2021, 3:39pm UTC](https://techcommunity.softwareag.com/t/nat0400-invalid-library-id/196513/2 "2021-04-02T15:39:20Z")

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