I have all of the actual expenses, but proconnect will not include the expenses in the return because I did not enter mileage. What should I do?

How do you expect the program to 'do the math' on the expenses if no mileage is entered to determine the business percentage?

Enter something for total & business to see what happens.

Altho... no mileage log really means no deduction IMHO...

Ten vehicles? Is this a type of business that all vehicles are used 100% for business?

As was mentioned, the program needs miles in order to calculate the business percentage of the vehicle.

"The client uses over 10 vehicles for his operation"

It needs to be asked...These all are owned by, deeded to, registered to, and insured by the business (entity), right? Not personal cars "doing business?" And what sort of proof is there for "business use" if there is not a trip log of some sort for each vehicle?

Look at page 2 of the 4562, Section C. "Answer these questions to determine if you meet an exception to completing Section B for vehicles used by employees who aren't more than 5% owners or related persons."

Then check any applicable boxes in the Autos and Other Listed Property section of the depreciation input.

No mileage log is needed if all vehicles are 100% business use.  If the software's attempt to be helpful results in a roadblock, drive around it by just entering 1,000 miles total and business, just so it doesn't try to substitute standard mileage rate.  (I doubt that's necessary, though.  Or you could estimate the mileage using cost of fuel and mpg.)