Okay, time to give an answer that's going to go into negative votes territory and stay there...
Yes, I can tell you that it's real: you don't have a circular reference, anywhere, and Excel is telling you that you've got one... somewhere.
And sometimes, it will tell you that it's Over here, Look! in a cell that definitely does not participate in a circular reference chain and often has no dependents at all.
Microsoft are never going to acknowledge this problem and they are never going to fix it.
A significant number of contributors to this site, and others, are never going to acknowledge that you do actually have a sheet with no circular references whatsoever, which is nevertheless raising a spurious error message. They, too are trapped in a spurious circular loop, and will only ever respond by giving you increasingly-patronising responses that explain how you will easily fix the circular reference that you do not actually have, by following a circular-reference resolution dialog that you'll never see.
The most galling version of this bug is the case when you really did have a circular error: you found it, you fixed it, and now you keep getting spurious 'circular reference' errors in cells with no dependents, no precedents, and no conditional formatting.
And, I cannot emphasise this enough, you do not have a circular reference.
Trust yourself, and do not give up and switch on iterative calculation as a mitigation.
Now for the bad news: there's no deterministic fix.
But let's try one anyway, and tell you how to use it as kludge:
You can sometimes fix this by deleting array formulas, saving and closing the file, and reinstating the arrays.
You can sometimes fix this by deleting lookup and conditional-sum formulas, saving and closing the file, and reinstating the lookups and conditionals.
The problem will recur, a few days later, when deep-calculating the sheet after 'fixing' it this way.
But, if you are the kind of person who always looks for lost quarters in the 'out' slot of a parking meter, I will offer you a suggestion that'll make you feel dirty:
Save the temporarily-fixed file as read-only, and get your sysadmin to set ownership and permissions so that this 'master' copy is never altered by your users.
The file is then a 'landmine' for anyone who takes it elsewhere and clicks 'Save As...' but the reappearance of the 'Circular error' message is now their problem.
...A a fix that might work, but I never succeeded with it:
I have never succeeded in eradicating the problem by removing the CalculationChain object from the xml and rebuilding the file: but try it anyway because I've heard it worked for someone, once.
...And the fix that actually works, but no-one wants to use:
I have only ever succeeded in fixing it by opening a new sheet, and copying across the formulas, formats, and conditional formats - in separate copy operations, not together with a simple ctrl-c and ctrl-v - one sheet at a time, and recreating the Names collection by hand.
I have verified, by hash signatures, that the text and formulae of the old and new sheets were identical and I do not doubt that the formulas were indeed identical.
And the new files worked without ever raising the spurious 'circular references' error again.
That's it. All of it. There is no other reliable answer.
Footnotes:
If you've come here in search of "Excel+Spurious+Circular+References" - and someone will, every few weeks or so, long after David Macintosh and I are the subject of intense debate among archaeologists examining the high-status grave goods and peculiar items 'of ritual significance' in our elaborately-decorated sarcophagi - I can well believe that you find this advice extremely unappetising; and I fully understand that you will probably file it away for use as a last resort.
And I feel that I should apologise if you only find this after reading several identically brilliant-but-misguided suggestions that your problem is your fault for using too many IF() branches, and that you shouldn't have used them at all. Those particular cultists are the reason for the sinister inscriptions that archaeologists really ought to read more carefully, and for the unexplained disappearance of several members of their excavation team.
