1. Open ArcCatalog and all tools within Python Toolbox(pyt) have a red-x error next to them claiming that "Arcpy module has no attribute Parameter"

  2. Close ArcCatalog

  3. Delete ArcToolbox.dat file in ~\AppData\Roaming\ESRI\Desktop10.2\ArcToolbox

  4. Open ArcCatalog, everything is fine with tools

  5. Run tools successfully

  6. Close ArcCatalog

  7. GOTO Symptom 1 .....

Seems like something in the geoprocessing results history is going wrong.

Any ideas for fixes?

I also want to maintain geoprocessing result history.

  • What does the tool do?
    – Hornbydd
    Oct 6, 2014 at 21:25
  • Some generic arcpy stuff, a couple Copys and cursors. Not much really.
    – bcollins
    Oct 6, 2014 at 21:53
  • 1
    I'm clutching at straws here...have you placed the pyt in some odd location that ArcMap cannot write to? Try placing it in a simple folder location like c:\temp? Just an idea really as it smacks of some sort of permission issue.
    – Hornbydd
    Oct 6, 2014 at 23:02
  • the .pyt file is in my home directory (C:/Users/bcollins). Also, if I disable the geoprocessing results history from Geoprocessing > Geoprocessing Options > Never Save, then errors go away.
    – bcollins
    Oct 6, 2014 at 23:45
  • I would try repairing the ArcGIS Installation...
    – MrBubbles
    Oct 9, 2014 at 12:05

1 Answer 1


I just experienced the same problem. It looks like ArcGIS is caching the tools/scripts. If I refresh (F5) the toolbox, after a few seconds the toolsets and tools would show-up and work, but next time I open ArcCatalog it shows the red crosses again. If you rename the folder where the PYT is stored, it won't show the red crosses the first time, only after you've run one of the tools inside the PYT toolbox.

Disabling the Geoprocessing Results works.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.