I'm having problems with arcgis 10.6

[NESLİHAN DAL]

Hello,

I have installed WhiteboxTool and I am using arcgis 10.6. But it doesn't do the analysis. There is a problem in the 'output file' part. It doesn't show a place to save the analysis. 

It says 'No description available'. What could be the cause of this error? How can I fix the problem on ArcMap 10.6.

Could you help me solve this problem? Thank you very much in advance.

Best regards 

Neslihan Dal