I would like to record that a cheque was written in error I picked up my mistake before the cheque was sent off and now need to use the next cheque in the book.

Recording a cheque that was mistakenly written is simple in QuickBooks Online (QBO), @Flex1. I'm gonna show you the way to achieve this. 

Before anything else, I'd like to know what specific error is shown when you try to save a cheque that you added a memo.  

We can record this transaction as a Cheque in QBO. Then, Void it and place the reason in the Memo section. This way the next Cheque number can be used just like in your book. 

Here's how: 

1. Click the + New icon.
2. Select Cheque from the Suppliers column.
3. Enter the Payee, Cheque no, and Category details. Then, add the reason why you'll void this cheque in the Memo field.
4. Once done, click Save and Close.

Check out this article for more information: Create and record cheques in QuickBooks Online. 

This time, we'll void this check. Feel free to follow the steps below: 

1. Go to the Expenses tab.
2. Find the cheque transaction from the Expenses section.
3. Click the dropdown icon below the Action column. It's also beside the View/Edit tab.
4. Select Void. 
   
   
5. Click Void again from the prompt message.
   
   

While we are waiting for what error you encountered, we can perform some basic troubleshooting steps to determine the root cause of your issue in saving a cheque that has a memo in your browser. 

Let's start by accessing your QBO account via private or incognito mode to avoid storing data cache files that can cause lag when using a web-based program. 

You can utilize these shortcut keys in your computer:  

• Google Chrome: press Ctrl + Shift + N
• Microsoft Edge: press Ctrl + Shift + N
• Safari: press Command + Shift +N 

Then, create and save the cheque. Once this works, clear the cache of your default browser to remove accumulated data files. If the issue persists, you can use another supported browser or device. 

Also, I'll share this article to help you learn how to record repetitive expense transactions easily: Create recurring transactions in QuickBooks Online.

Have more questions about recording Cheque transactions in QBO? Don't feel shy sharing them with us. It would be our pleasure to assist you in all possible ways. Keep safe, and have a good day.