How to upload bank deposit account into QB?

Glad to have you here in the Community, @Jacky007.

Usually, this error occurs when there's too much cache in the browser. To fix this, let's perform some troubleshooting steps. Let's start by accessing QuickBooks (QBO) account using a private browser. The following are the shortcut keys you can use:

• Google Chrome: press Ctrl + Shift + N 
• Mozilla Firefox and Microsoft Edge: press Ctrl + Shift + P
• Safari: press Command + Shift + N

If this works, you can clear the cache and cookies of your browser. If not, you can use another supported browser. Possible that your current browser may have a temporary issue with QuickBooks.

Also, ensure to use the correct format or mapping when importing CSV files. Otherwise, QuickBooks Online (QBO) won't be able to read your data. To resolve this, you can refer to this article: Fix errors when importing CSV.

Once everything's good, you'll want to pull up the Deposit Detail report to keep track of all your deposits, with the date, customer or vendor, and their amounts. Just go to the Reports menu, and select the said report from the Sales and customers section.

Also, you can categorize and match your entries to make sure they're accounted for correctly and prevent any duplicates. Then, reconcile your account to ensure the accuracy of your books.

I've got your back here in the Community if you have more questions about managing your transactions in QBO. Just add a comment below so I can assist you further. Take care.