Hello there, @Zsofica.

This is not what we want you to experience. It's my priority to ensure you'll be able to keep a handy copy of your data and I'll ensure you can see your missing transactions in QuickBooks Self-Employed (QBSE).

Errors when uploading transactions can happen when the format is not correct. To isolate this issue, you can upload CSVs with either the following 3-column or 4-column format. 

On the other hand, you'll want to check the CSV formatting styles. Also, know that the maximum file size is 350 KB to successfully upload those transactions in QuickBooks. 

You can fine-tune the formatting if you receive an error message when you upload the file. 

• Remove any zeros (0) from the file. Leave those cells blank.
• Correct any transactions that display numbers in the Description column.
• Remove the word "amount" if it appears in the Credit or Debit column header. They should only read "Credit" and "Debit" without the word "amount."
• Make sure the dates are in one format. We recommend you use: dd/mm/yyyy.
• Mac users must save the file as a Windows CSV file.
• Some banks add the day of the week in the Date column (for example, 20/11/2018 TUE). You need to remove the day of the week. To do this, split the date and the day of the week into separate columns: 

1. Open the CSV in Microsoft Excel.
2. Highlight the column that contains the date.
3. Go to Data then select Text to Columns.
4. Follow the onscreen steps and select the following:
   • Original data type: Delimited
   • Delimiters: Space
   • Column data format: General

Once your file is formatted correctly, you can try to re-import the transactions again. You can read this article for more details about manually importing transactions in QBSE: Manually import transactions into QuickBooks Self-Employed. 

Once you're done, go to the Transactions menu and categorize your imported transactions. This way, QuickBooks puts them on the correct line of your Schedule C.

Additionally, you may want to check out one of our Help pages as your reference to guide you in managing your bank transactions and connectivity in QBSE: Banking Help for QuickBooks Self-Employed.

Feel free to get in touch with us if you need additional assistance with your missing bank transactions in QBSE. We'll be here to help you all the way. Keep safe.