I'm here to take care of your concern today, @office90.

It's all good. We have the steps on how to make inactive clients back to being active again. I'm happy to guide you on how.

1. Open your QuickBooks Desktop file, then select Customer Center from the Customers menu.
2. Go to the Customers & Jobs section, then select All Customers from the drop-down.
3. Inactive customers have X mark beside their names. To make them active, right-click on the customer's name, then click on Make Customer: Job Active.

In case you want to merge your accounts, customers, and vendors lists, you can read the details from this link as your guide.

Also, feel free to skim through the information from this article to learn more about the different ways you can track customer transactions in QuickBooks Desktop: Get started with customer transaction workflows in QuickBooks Desktop.

Just in case you're using QuickBooks Online, you can check out the instructions provided from this article on how to activate a customer again: Make a customer inactive and then active.

Thanks for allowing me to help. If you have any other questions, feel free to add a comment below. Have a good day!