# Virtual Things add on

**URL:** https://discourse.mozilla.org/t/virtual-things-add-on/107896
**Category:** WebThings
**Created:** [November 19, 2022, 12:25am UTC](https://discourse.mozilla.org/t/virtual-things-add-on/107896 "2022-11-19T00:25:28Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![mark\_lennan](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@mark\_lennan](https://discourse.mozilla.org/u/mark_lennan)
#### Post date: [November 19, 2022, 12:25am UTC](https://discourse.mozilla.org/t/virtual-things-add-on/107896/1 "2022-11-19T00:25:28Z")

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Hi all,  
Has anyone had any experience adding more than 1 Virtual Thing?  
Im having trouble creating a 2nd Virtual Thing.  
Ive created 1 and it works all ok but when trying to create a 2nd i always get an error at top of screen-  
.customThings[0].properties[0].default should be string  
Ive tried everything and i get this same error no matter what i do and i cant see what its asking for.  
Any ideas anyone? The 2nd Virtual Thing im trying to create is the same as the 1st one that is working.  
Here is screenshot of error-

 ![Screenshot from 2022-11-17 19-36-41](https://us1.discourse-cdn.com/flex001/uploads/mozilla/original/3X/b/e/beeec03863af1b1512189f34d531d2d66351b94c.png)

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### Author: ![EricEdberg](https://sea1.discourse-cdn.com/flex001/user_avatar/discourse.mozilla.org/ericedberg/32/29005_2.png) [@EricEdberg](https://discourse.mozilla.org/u/EricEdberg)
#### Post date: [November 19, 2022, 12:24pm UTC](https://discourse.mozilla.org/t/virtual-things-add-on/107896/2 "2022-11-19T12:24:54Z")

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Seem to remember that this error message was displayed each time I created a new virtual device too? It never affected creating them however…

I’ve created many virtual things to mirror my X10 device states managed by a CM15 and also used as state machines logic nodes.