Workflow to send mail 20 day before the expiry date

Question

Dear All,
I created a workflow to send mail when a calculated column date is equal to today as follows:-
Step1
add -20 days  to Current Item:Expiry Date (Output to Variable : date)
then set variable : Notification1 to Variable : date
Step2
If variable:notification1 equals (ignoring time) Today
email users
Now when i add a new item to the list , the workflow status is set to In progress , and when i refresh the page the status is changed to Completed before the condition is met and!!
Any help
Regards

Answer 1

If I Understood your question correctly, you need to send email to user 20 days before expiration date. 
From above you workflow I can see, you are just checking your condition once a item is created. As your Step2 condition is not met your  workflow is completed without any error. I suggest you might want to try below workflow
Step1
add -20 days  to Current Item:Expiry Date (Output to Variable : date)
then set variable : Notification1 to Variable : date
then Pause until Variable:date
Step2
email users
Above workflow design will pause you workflow till 20 days before expiry date. and then send email to user. 
Please ignore syntax, I just tried to put logic.
Below is explantion on how to use Pause Action(from MSDN) in Sharepoint workflow
This action is initially displayed in a workflow step as Pause until this time.
Use this action to pause the workflow until a particular date. You can add a current date, a specific date, or a lookup.
Following are examples of what the action might look like in a workflow step,
Pause until 1/1/2010 12:00:00 AM
Pause until Variable: A week from Modified
If this helps Please mark it answer or vote as helpful.
Thanks
Siddharth