Error ERROR Validation Error Compiler error(s) encountered processing expression ""C:\Users\sjahedba\Documents\UiPath\ExcelAutomation\jahed.xlsx"". Value of type 'String' cannot be converted to 'UiPath.Excel.WorkbookApplication'. test.xaml

Hi Maciej,

Again i came with new error.

I would need a your wonderful help hand.

Error what i am getting !

Step 1) Below screenshot is my work flow

Step 2 ) While using the “Run file” --> successfully ran the flowchart and i am getting output


Step 3) While using the " Debug" flowchart throwing an error.

Step 4 ) Based on the above error , i assuming the “Send outlook mail message” activity having issue – > Primary issue in “Attach file”

Step 5 ) For your reference i am sharing list of variable used in my flowchart from variable panel


Instead of Hardcoded value, try to assign to a variable and pass that variable

Hope it works


Hy @shaik.jahedbasha570,

Could you check if all the libraries are updated? It is unusual error

Hi Srinu,

i tried this , i have two observation.

1 ) by using the assign activity i have given file path but getting error , please find the below screenshot


could you please hoover your mouse on the warning icon so we can see the message?


Hi Willim,

i have shared the screenshot.


is this help!


Hy @shaik.jahedbasha570,

The argument passed needs to be a “String”, not array of strings as you passed, you are almost there :slight_smile:

Hi William,

Please find the below images

Hy @shaik.jahedbasha570,

The ‘Directory.GetFiles’ activity returns an array of strings, do you need to send a single file or more than one?
If it is only one type attachementpath(0) to get the first item, that is to be the only one.
If are multiple try using the ‘AttachementCollection’ property instead.

Please let me know if it works :slight_smile:

hi will,

am i doing to right way !

You came back to the same issue as before,… Are your libraries up to date? Its odd!

hey will,

kindly guide me , which libraries , would i add !

@shaik.jahedbasha570, just show me a screen shot of the libraries on your project

hey Will,

i am new to Uiapth ,

is this are you looking

@shaik.jahedbasha570, please uncheck the ‘Include Pre release’

After that update all the packages and try running it again