Run Command generating Error Code 255

[elamp6]

I am receiving Error Code 255 when I attempt to run my workflow using the following command:

'cd ' + [directory]+'\ && For %f in (*.xml) do type "%f" >> combined.txt & echo. >> combined.txt'

When I remove the command following the mkdir command, the workflow executes correctly. Does anyone know what I need to change? 

I am ultimately trying to concatenate some xml files and output the combined file. 

Workflow is attached!

[SPetrie]

You need to escape the % variable in a batch file.

Update your formula to be 

'cd ' + [directory]+'\ && For %%f in (*.xml) do type "%%f" >> combined.txt & echo. >> combined.txt'

Side note, an alternative way to achieve it would be to use

'For /R ' + [directory]+' %%f in (*.xml) do type "%%f" >>' + [directory]+'combined.txt'