Thanks for joining this thread, d00b1e.
 

You're correct, as DHeraV's post mentions, inactive customers can be reactivated one at a time. You can do so by following the steps in MaryGraceS's post.
 

I can certainly understand how an ability to reactivate multiple customers at the same time could be useful and have submitted a suggestion about it as of today.
 

You can also submit your own feature requests while signed in.
 

Here's how:

1. Use the Gear () icon, then go to Feedback.
2. Enter your suggestion(s) in the Have feedback? window.
3. If necessary, attach a file with your Camera () icon.
4. Select Next.
   
   

Your feedback's definitely valuable to Intuit. It will be reviewed by our Product Development team and considered in future updates. You can stay up-to-date with the latest news about your product by reviewing Intuit's Product Updates webpage.
 

I'll be here to help if there's any questions. Have a lovely day!