| Well, you have to understand that a trial balance not coming out may not just be because an entry was not posted correctly... or I don't know what that comment is about contra entries. Everything isn't about contra accounts and it's not relevant whether it's contra or not. And classifying them correctly is also irrelevant because it won't put you out of balance.
It's about math, plain and simple. If each entry balances to begin with, if it is posted correctly, if the account is then balanced corrected, if it is then copied to the trial balance correctly, and if then the two columns are added correctly, the trial balance will come out equal. EVEN IF any of your entries are incorrect. i.e. what if you were supposed to debit cash and you debited accounts receivable? That still balances, even if it's wrong. You could even debit payables (a different classification) and it'll still balance. It has to be specifically a mathematical thing. (An important note here is that a trial balance balancing does not mean everything is correct. It means the debits & credits came out equal, nothing more.)
Everything I just listed above is mathematical, and those are the things that need to be checked. I don't know what the UBS Accounting System is. I'm going to assume that's a computerized system. If that is the case, usually they don't let you get out of balance, so that's a bit of a surprise. (i.e. any computer software for accounting usually does the math for you and gives you warnings that something is out of balance. Perhaps that green light you're talking about?) So I can't tell you specifically in that system how to check for it. If the whole thing does the math for you and every entry balances, I really have no idea how it could've gotten out of balance. (Technical problem?)
When we do it manually, we have to just start working backwards. i.e. re-add the columns. Then check that all account balances got onto the trial balance correctly. Then check the math in every account, etc. The unfortunate answer is that there usually is not some quickie way to figure it out, unless you get lucky. If you figure out the difference between your two columns, check to see if that number has some meaning to you. (Look through entries and accounts and see if that number exists somewhere.) Also divide the difference in two and see if you can find that number.
But I'm giving you manually ways to figure it out. If this is computerized, honestly I just don't get how it got out of balance to begin with. | 
Linear Mode
