Is it possible to re Sync the prior years transactions from Quickbooks self employed to Quickbooks ONline?

You can use MT Online or one of the converter tools (e.g csv2qbo @ $60 one time license) as a workaround.

https://www.moneythumb.com/?ref=110

Yes, @herbiewalbanker, it's possible. Let me share some information about syncing transactions from QuickBooks Self-Employed (QBSE) to QuickBooks Online (QBO).

Before doing so, can you tell me if these transactions were previously synced to QuickBooks Online?

If you're switching from QBSE to QBO, you can easily move your data to the online version. If you plan to connect the same bank accounts you used in QuickBooks Self-Employed, you don't need to move any transactions. Instead, follow the steps to connect your accounts. QuickBooks will automatically download several months of recent transactions. The Online Banking feature saves time and avoids importing duplicates.

For more information, check out this article: Switch from QuickBooks Self-Employed to QuickBooks Online. 

Once your transactions are in QuickBooks Online, go to the Transactions menu, then select Bank Transactions. Follow the steps to review and categorize your transactions.

Drop your comment below if you have other questions or concerns about moving transactions to QuickBooks Online. The Community team is always around to assist.

My banks are connected.  I have about 4-5 years of categorized business expenses for P and L statements.  All those years I can’t get synced again.

My banks are already connected.  I’ve lost access to several years of categorized transactions for P and L statements and tax purposes

I'm here to help you add the transactions, herbiewalbanker.

When linking your bank and credit card account for the first time in QuickBooks, you can choose the timeframe for downloading transactions. Some banks offer the last 90 days, while others provide up to 24 months, depending on your bank. With that, syncing data beyond this timeframe, such as from the past 4 to 5 years, is unavailable.

Additionally, when your categorized transactions transfer from QuickBooks Self-Employed (QBSE) to QuickBooks Online (QBO), please note that the categories may not remain the same due to differences in category structures between the two platforms.

Furthermore, if you want historical data beyond what QuickBooks can sync, you may consider uploading your transaction manually into the system. Before doing so, I recommend reviewing your reports to prevent duplicates. Then, if necessary, you can recategorize them accordingly.

Here's how:

1. Sign in to your bank's website and export your bank transactions.
2. In your QBO account, go to the Banking menu.
3. From the Update drop-down, select File Upload.
4. Click Browse and select the web-connect file from your bank.
5. Follow the on-screen steps in mapping the data.

Check this guide for more details: Manually upload transactions.

You might find the following articles helpful about adding and matching transactions in QBO: 

• Reconcile an account
• What to do if you get a bank error or can't download transactions

Keep me posted if you have other questions about managing transactions in QuickBooks. I'll make sure to get back to you as soon as I can.