I can not export complete checking register?

Hello there, @Rick_Young.

Let's make sure you select the Enable Editing option and keep Excel updated so you can export your complete checking register in QuickBooks Online (QBO). This way, you can manage your transactions accordingly.

You can export your complete checking register (which goes back to when you started your account) in QBO using the Export icon. When you have missing data while you open the report in Excel, the file is in protected view. To fix this, you'll have to select the Enable Editing option and then make sure you have an updated Excel application.

To fix this, you'll first have to make sure you click the Enable Editing option for the Excel file to view the full report. Please see the screenshot below for your reference.

In case the issue persists, I recommend updating your Excel application. This way, you can export your complete checking register. Here's how:

1. Open the Excel file.
2. Navigate to the File menu.
3. Select Account. 
4. Click Update Options.
5. Select Update Now. In case you don't see the Update option, you already have the latest version of Excel.

Once you're done, go back to your checking account's register and select the Export button to reexport your data.

Feel free to read this article for more details: Export reports, lists, and other data from QuickBooks Online.

Also, you may want to check out one of our Help pages as your reference to guide you in managing the growth of your business and everyday transactions using QBO: QuickBooks Lear and Support. It includes QuickBooks help articles, Community discussions with other users, and video tutorials, to name a few.

Please keep me posted on how it goes in the comments below. If you have other exporting concerns or questions about managing transactions in QBO, I'm always ready to help. Take care, and have a great day, @Rick_Young.