# Processing fails after adding GCPs

**URL:** <https://community.pix4d.com/t/processing-fails-after-adding-gcps/8088>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [March 21, 2019, 7:40am UTC](https://community.pix4d.com/t/processing-fails-after-adding-gcps/8088 "2019-03-21T07:40:30Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Timo\_Hakkarainen](https://avatars.discourse-cdn.com/v4/letter/t/eb9ed0/32.png) [@Timo\_Hakkarainen](https://community.pix4d.com/u/Timo_Hakkarainen)\
**Post date:** [March 21, 2019, 7:40am UTC](https://community.pix4d.com/t/processing-fails-after-adding-gcps/8088/1 "2019-03-21T07:40:30Z")

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Hi,

I’ve a project which repeatedly fails processing after adding GCPs. After adding GCPs and clicking “Reoptimize”, software works for a while, then just crashes to desktop with no error messages.

If I add GCPs and start processing STEP 1 again, processing fails at computing uncertainty, with error “[Error]: Caught unknown exception during initial processing!”

If no GCPs are added, project successfully processes throught all steps.

This same dataset has been previously succesfully processed using GCPs (this was our demo-dataset when we were purchasing our drone) in spring 2017.

Project logfile: [https://1drv.ms/u/s!Au0dLfpkWadVhb9MjHOpjv4-e0\_XBQ](https://1drv.ms/u/s!Au0dLfpkWadVhb9MjHOpjv4-e0_XBQ)

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**Author:** ![Daniel\_Rico\_Cordero](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/daniel_rico_cordero/32/187_2.png) [@Daniel\_Rico\_Cordero](https://community.pix4d.com/u/Daniel_Rico_Cordero)\
**Post date:** [March 25, 2019, 9:56am UTC](https://community.pix4d.com/t/processing-fails-after-adding-gcps/8088/2 "2019-03-25T09:56:21Z")

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Hello Timo,

I would say that there is something going on with the GCPs. Has the proper coordinate system been selected for the GCPs?

Does the Pix4D MapView show both GCPs and images in the right position?

Would you please send the Quality Report and the GCPs file?

Thank you very much.

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**Author:** ![Timo\_Hakkarainen](https://avatars.discourse-cdn.com/v4/letter/t/eb9ed0/32.png) [@Timo\_Hakkarainen](https://community.pix4d.com/u/Timo_Hakkarainen)\
**Post date:** [March 25, 2019, 10:28am UTC](https://community.pix4d.com/t/processing-fails-after-adding-gcps/8088/3 "2019-03-25T10:28:49Z")

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Hi,

You were right. There was some extra fields in my GCP csv file after the coordinates. The earlier version of Pix4D apparently ignored them, but current version doesn’t know how to intepret the fields, and removed the accuracy information of GCPs.

Removed the extra fields, and now project processes normally.

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**Author:** ![Daniel\_Rico\_Cordero](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/daniel_rico_cordero/32/187_2.png) [@Daniel\_Rico\_Cordero](https://community.pix4d.com/u/Daniel_Rico_Cordero)\
**Post date:** [March 25, 2019, 12:26pm UTC](https://community.pix4d.com/t/processing-fails-after-adding-gcps/8088/4 "2019-03-25T12:26:27Z")

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Hi,

Thanks for your comment and feedback.