Salaried/vacation time?

What is the name of your state? IL

I'm considered a salaried employee and I sometimes work partial days because I've worked extra hours on other days. My company is now forcing me to use 1/2 a day of vacation time for these partial days. Can they do that for a salaried employee? (the company has no written policy in regards to comp time for salaried employees)

"Salaried" is merely a pay method and has no legal standing. Do you mean to say that your position is exempt under the FLSA? If so, there is no requirement to allow you comp time for extra hours you work and yes, they may attribute any absence time to your vacation. It may not be a great idea but it is legal.

I think I would be considered exempt. I manage a warehouse, but the majority of my duties are non-manual, office work...

If you are exempt, your employer may but is not required to provide you with comp time, and may if they so choose attribute any absences to vacation time.

If you are non-exempt, your employer is specifically forbidden by law from allowing you to take comp time, but still may attribute absences to vacation time. However, in that case, if you work more than 40 hours in a week, (that's WORK more than 40 hours - vacation, sick, personal and other paid leave time does NOT count) they must pay you overtime.

If they consider that all my vacation time is used for the year, can they then dock my pay for any time I might miss, even if it's just an hour or two?

Now THAT really does depend on whether you are exempt or non-exempt.

If you are non-exempt, then yes, they can dock you for any time you don't work. Nothing in Federal law and nothing in Illinois law requires them to pay a non-exempt employee for time they are not actually on the job. In fact, in the entire US, the only exceptions to that are a very small handful of states (NOT IL) which requires paid time off to vote, and some limited medical leave in California.

However, if you are exempt the only time they can dock your pay in partial day increments is if you are on FMLA.

They CAN dock an exempt employee in whole day increments in some, limited circumstances. But they CANNOT dock your pay (your vacation, sick or personal time yes - your pay no) in partial day increments under ANY circumstances except the one exception in the paragraph above.