Can you clarify exactly where you are trying to paste? When I reconcile, I use the middle “Use statement balance” radio button, and I enter the balance in the “Ending Balance” box. Is this what you're describing, or something else? I just tried typing a number (12,345.67) in this text editor, copied that text, and pasted it into the Ending Balance box — successfully.
@jacobs If you reconcile an account that's not connected for online access, the left hand option changes from “Use online balance” to “Use current balance”. I'm not sure how that differs from “Use statement balance”.
In any event, I'm not having any problem pasting numbers into that field. Make sure when you select the balance text in your browser that you're not inadvertantly selecting anything else - it's easy to pick up extra white space characters like tabs or new lines that can mess up a text entry box.
@Robin Whyte I tried cutting & pasting balances using Safari on several websites where I have accounts and they all worked fine doing it just as you describe - double click on the number, then copy & paste into the Current Balance window. The number displayed correctly in the window and Quicken didn't complain at all when I clicked on the Next button.
I then tried Firefox and it didn't go so well. First, double-clicking didn't select the entire balance, just part of it (if the balance was $123.45, double-clicking would pick up either “123” or “45”). I had to triple-click to get the whole thing but then it would pick up the “$” character as well & Quicken didn't like that - the selected text pasted into the window just fine but when I clicked on the Next button I got the error beep. I had to click & drag to select the balance without the $ and then Quicken was happy.
So it still seems to me like you might be picking up extra characters somehow. Have you tried pasting the balance into some other application, such as TextEdit, to see what gets pasted in? Or clicking & dragging to select the balance instead of double-clicking?