Solopreneur isn't working like it should since I had to switch from self-employed. 1) I can't mark old invoices paid. I search for the invoice # but it isn't found.

Let's work together in managing tasks of your customer sales transactions in QuickBooks Solopreneur (QBSP), coachcheryl.

When recording customer-paid invoices, let's ensure you've selected the correct Deposited to bank option to link the payment transaction available to the open invoice entry. If the transaction isn't visible yet, your bank is still processing it. 

On the other hand, you'll need to make sure filters are applied when searching for the invoice reference number from the Search section. Review all details so all transactions are available. I'm also including this reference to guide you in managing customer invoice transactions: Create invoices in QuickBooks Self-Employed.

For issues two & three, sometimes stored cache files can cause an interruption while using the program features. Let's consider performing some troubleshooting steps to rule out the possibility of a browser issue. I'd suggest opening your QBSP account in a private window. You can refer to these keyboard shortcuts to open one:

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

If these details are successfully populating, you may go back to your default browser and clear its cache or use a different supported browser.

Moreover, you can utilize this resource to learn more about the program and its features: Introduction to QuickBooks Solopreneur.

If there's anything else you need further assistance with when managing your account, keep me posted in this thread. I'll make sure to provide the best help, so you can keep your business going. Stay safe and have a great day ahead!