I can share additional information in resolving this, @Globalksp.
Thank you for trying the steps that are provided by AileneA & Ryan_M since you're still unable to mark up Items in the Billing Time & Expense window. Then, I suggest reaching out to our Customer Support.
They have the additional tools which can troubleshoot the error you're having and help you resolve it.
You can follow the steps below on how to reach them:
- From your QuickBooks Desktop account, click the Help menu at the top.
- Click the QuickBooks Desktop Help menu and select QuickBooks Desktop Help.
- Provide some information about this concern on the search box.
- Click the Contact Us link at the bottom of the window.
- You'll now be provided with a few support options.
- Select Get a call to arrange a callback from a support agent. Or Start a chat to chat with them directly.
Here's the contact QuickBooks Desktop support article for more information about this.
Let me know if there's anything that I can help you with your account. I'm always here to assist. Have a wonderful day!