# Custom filters spread like viruses

**URL:** https://discourse.paraview.org/t/custom-filters-spread-like-viruses/2597
**Category:** ParaView Support
**Created:** [September 20, 2019, 10:05am UTC](https://discourse.paraview.org/t/custom-filters-spread-like-viruses/2597 "2019-09-20T10:05:39Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![lhofmann](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/l/9e8a1a/32.png) [@lhofmann](https://discourse.paraview.org/u/lhofmann)
#### Post date: [September 20, 2019, 10:05am UTC](https://discourse.paraview.org/t/custom-filters-spread-like-viruses/2597/1 "2019-09-20T10:05:39Z")

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ParaView seems to append all custom filters to any statefile that is saved (even custom filters that are not used), and further stores any custom filter, that is read from a statefile, in the local config.

This way, custom filters spread like viruses. We noticed this, when a member of our lab created a custom filter using an external plugin, that is no longer available. Anyone, who loaded one of his statefiles, was greeted with an error message, and all future saved statefiles had the same effect on any unsuspecting user’s ParaView.

To reproduce:

1. Load the example statefile [example.pvsm](https://discourse.paraview.org/uploads/short-url/dqJmd2G3Tk7lXvm3HQXFv1acFsm.pvsm) (1.9 KB)
2. (optional) restart ParaView -\> error message is printed
3. Save a new statefile
4. Delete your ParaView config (or pass the statefile to someone else) and load the new statefile -\> error message is printed
5. goto 3

Of course, this can be easily fixed by deleted the corresponding custom filter via Tools-\>Manage Custom Filters, but since most of us never used this feature, it took us a while to figure that out.

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### Author: ![wascott](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/w/8e8cbc/32.png) [@wascott](https://discourse.paraview.org/u/wascott)
#### Post date: [September 20, 2019, 7:24pm UTC](https://discourse.paraview.org/t/custom-filters-spread-like-viruses/2597/2 "2019-09-20T19:24:59Z")

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Written up here: [https://gitlab.kitware.com/paraview/paraview/issues/19340](https://gitlab.kitware.com/paraview/paraview/issues/19340)

Thanks for reporting, and the great bug report.

Alan

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### Author: ![utkarsh.ayachit](https://discourse.paraview.org/user_avatar/discourse.paraview.org/utkarsh.ayachit/32/39_2.png) [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [November 1, 2019, 6:44pm UTC](https://discourse.paraview.org/t/custom-filters-spread-like-viruses/2597/3 "2019-11-01T18:44:38Z")

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This should now be resolved in ParaView master and will be included in ParaView 5.8. Here’s the [MR](https://gitlab.kitware.com/paraview/paraview/merge_requests/3679) that fixes it.