Thanks for reaching out in the QuickBooks Community, @jonathanknee.
Once you reconnect your account in QuickBooks, the program will automatically remove all of your transactions and redownload them again. However, only your past 90 days' worth of banking data will be redownloaded.
This is why some of your old banking transactions aren't showing in the Transactions menu.
If you want to add them again, you can export them from your bank and import them into QuickBooks using your laptop or desktop. Here's how:
- Sign in to your bank’s website.
- Follow your bank’s steps to download your transactions as a CSV file. This is usually a button or link on your account page.
- Set the date range for at least one day before the oldest transaction in the account in QuickBooks.
- Follow any on-screen instructions to finish the download.
Once done, follow step number 3 in this article: How to import the transactions using CSV file in QBSE.
Before you get transactions from your bank, please check which ones are already in QuickBooks so you don’t add duplicates.
When you're done, review and categorise your bank transactions to put them in your accounts.
The Community always has your back, so please let me know if you have any other questions. I'll be more than happy to help. Keep safe.