Value cannot be null . Parameter name : expression file: main.xaml

[dnandhini232]

hi my work flow was running fine Until today but now when i try to run . I am getting an error like this …why am i getting validation error all of sudden . Dint make any changes to workflow

[Hiba_B (Hiba Beldi)]

Hi @dnandhini232 !
When you look at the arguments of the Main, do you see null values ?

[postwick (Paul)]

It looks like the error is related to an activity, not an argument. Arguments are allowed to have null values.

[postwick (Paul)]

In Error List, double-click the error and it’ll take you to the activity that’s causing the error.

[dnandhini232]

I tried double clicking on it. It doesnt take me to any activity .

[postwick (Paul)]

In the Output pane, or Error List pane? You need to be in the Error List pane.

[Serban (Serban Ungurelu)]

Hi everyone,

Having the same issue. Normally i’d double click on the error in the Error List pane and Studio would automatically open the workflow file, and the activity in question would be flagged. It’s not doing that for this workflow.

I’ve manually checked the workflow and it looks fine. To be fair I could have missed something since it’s a rather complex workflow.

I’ll check again. Until then, anyone have any ideas? @postwick thoughts? thank you very much!

[Serban (Serban Ungurelu)]

UPDATE: Figured it out. I triple-checked the workflow, it had to do with the ‘On Element Appear’ activity’s ‘RepeatForever’ attribute. I had left that field empty by accident. Once i remedied that, everything worked, workflow validated.