Why can't I print invoices all of a sudden

Let's investigate what's causing this issue and perform some troubleshooting steps to print your invoice, mike253. 

Have you encountered an error message? This helps us check if there's a reported case about this one. 

It'possible your browser's cache data becomes full of frequently accessed websites. It could be your browser's cache data is damaged preventing you from printing your invoices. 

To better isolate this one, let's try signing in to your QuickBooks Online (QBO) account using a private or incognito window. This mode doesn't use the existing cache data and helps us confirm browser-related issues.

You can use either of these keyboard shortcuts:

• For Google Chrome browser: Ctrl + Shift + N
• For Mozilla Firefox browser: Ctrl + Shift + P
• For Safari browser: Command + Option + P

Then, try printing an invoice again. 

If it works, then your main browser may have too much historical data from previously visited websites that cause this kind of behavior. Just go back to your regular browser and clear the cache to delete those temporarily stored files and browsing history. You can also use other supported, up-to-date browsers to roll out the possibility of a browser-related issue.

I have articles here that provide you with troubleshooting solutions about resolving printing issues: 

• Fix QuickBooks Online printing issues on browsers for Windows
• How to update, repair, or re-install Adobe Reader/Acrobat
• Test sequence for PDF printing issues

That'll do it. I'll be right here to continue helping if you need a hand with customizing sales forms or any QBO related. Assistance is just a post away. Have a great day ahead.