# System.tag.exists in expression error

**URL:** <https://forum.inductiveautomation.com/t/system-tag-exists-in-expression-error/97563>\
**Category:** Ignition\
**Created:** [October 21, 2024, 7:35pm UTC](https://forum.inductiveautomation.com/t/system-tag-exists-in-expression-error/97563 "2024-10-21T19:35:44Z")\
**Posts on this page:** 1\
**Showing post:** 10

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**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [October 22, 2024, 2:51am UTC](https://forum.inductiveautomation.com/t/system-tag-exists-in-expression-error/97563/10 "2024-10-22T02:51:54Z")

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> [@lrose](#):
>
> `isBad()` or `isBadOrError()`

Or `isAvailable()` from Paul's [Ignition Extensions](https://forum.inductiveautomation.com/t/ignition-extensions-convenience-utilities-for-advanced-users/64615/5) module, which checks if the tag is both not disabled and exists, because those are the only two states in which you would want to hide something using, otherwise you would be masking a genuine issue. (to test for these two qualities without `isAvailable` is a horrible monster of an expression)

Still hoping that this makes it into the product!!!!

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