David,

Two questions,

1. What platform are you running on SharePoint or O365?  

2. Could you share your workflow design or even export it to us?

Also, any screenshots of the permissions settings would be good. 

A quick thought, if the user has full control of the site, are the list inheriting from the site? If so then the user would have full control of both lists which is what you noted. However, the workflow would need permissions to operate on behalf of the user and I believe this setting called Workflow can use app permission at the site level would need to be set. Check for Site Settings > Manage Site Features.

My screenshot if from Office 365 but it should apply if you're on SharePoint

I have SharePoint Enterprise.  The user has full control of the list, but note the list has unique permissions (not inherited).  The user also has Full Control at the site level.  I did try to activate the "Workflows can use app permissions", but I got the message "Sorry something went wrong"

If the list has unique permissions, be sure that the person generating the item via the workflow has at least create permissions on that list. Regardless of Full control on the site, the list will override that if permissions are changed.  This allows SharePoint to manage item level control, even with a site owner having full control.

I'd bet that's where you're seeing the issue. Try inheriting and running a few test. If it resolves ypur issue. Figure out a different permissions method for the list.

Eric

Could be because the workflow is running under a different person who published it who has less privilege in the library.

When I go to the list and view permissions - permissions are unique and this individual has Permissions at "Full Control".  Thus at the site level he has Full Control and and at the list level he has Full Control.  The list currently does not inherit permissions, thus within the list I selected his name and the permissions of Full Control. Are you indicating this method will not work and I need to change the list to inherit permissions ? 

What would I need to do to correct this...

Hope the user has permission on both list A and ListB, can try to run the workflow without mentioning the content type. let it create the default.

David,

What are the permissions settings on the list? I think I got what you said with you gave him direct permissions to the list itself. 

Steps to test this out. 

1. inherit from the site

2. test the workflow for yourself and the other user

3. if it works, you have a permissions conflict on the list

4. if it doesn't work, try Sojan's suggestion to redo the action to use the default content type "document" and not selecting document type.

Any chance for a screenshot? 

I will try tomorrow

I will try tomorrow

I let it select the default and it worked !  In addition though I changed the extension from an xlt extension to xlsx for the default document.

David -  Have you checked the workflow task list permission level for that users because some time we have break the permission level for list also.?

What do you mean by workflow task list permission - are you referring to the list permission.