# system.tag.readAll override

**URL:** <https://forum.inductiveautomation.com/t/system-tag-readall-override/9526>\
**Category:** Ignition\
**Created:** [January 12, 2015, 11:05am UTC](https://forum.inductiveautomation.com/t/system-tag-readall-override/9526 "2015-01-12T11:05:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Amarth](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarth/32/3313_2.png) [@Amarth](https://forum.inductiveautomation.com/u/Amarth)\
**Post date:** [January 12, 2015, 11:05am UTC](https://forum.inductiveautomation.com/t/system-tag-readall-override/9526/1 "2015-01-12T11:05:07Z")

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Hello and happy new year,

A client of mine has, by mistake, redefined a system function (sytem.tag.readAll) by assigning a value to it in a script :  
system.tag.readAll = 42 (for example)

Now and even after a Gateway restart, the function system.tag.readAll does not exist anymore (as it has been redefined). Calling a system.tag.readAll() raises an error.

I managed to get it back by re-installing the Gateway, but is there a easier way to undefine/unset/reset a function to its initial definition ?

Thank you.

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**Author:** ![Amarth](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarth/32/3313_2.png) [@Amarth](https://forum.inductiveautomation.com/u/Amarth)\
**Post date:** [January 12, 2015, 12:47pm UTC](https://forum.inductiveautomation.com/t/system-tag-readall-override/9526/2 "2015-01-12T12:47:30Z")

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Removing the cache (c:\users\xxx.ignition) seems to do the trick.

Is there a way to prevent a redefinition of these functions ?

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [January 12, 2015, 11:32pm UTC](https://forum.inductiveautomation.com/t/system-tag-readall-override/9526/3 "2015-01-12T23:32:27Z")

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I don’t think there is anything you can do to prevent a user from overriding or redefining a system function.