I'm not sure I have an answer for you but I do have a couple of questions.

First, does your inventory valuation report reconcile with the inventory accounts?

Second, what do the related tabs (especially Cost Detail) in Item Maintence say?

If those two things don't reconcile then I would suspect data corruption for which I call my reseller.  If they do I would try playing with the utilities in IM and Library Master (in a test company) and see if any of them fix the problem.

Best of luck.

Nicholas

What is the valuation method of the items?  What might have happened is that you have one cost tier with one on hand with a cost of $1,000 and one cost tier with a negative one on hand with a cost of $900. In this case the system would correct show zero on hand and a valuation of $100. Run the Negative Tier Adjustment and see if this clears it up.

I'll toss this out in case it helps, if your valuation method is average cost, depending on what version you're on and the valuation method, there's been a number of issues with the average cost calculations since the inventory module framework change that have been fixed over time, but the effects of those programming issues will linger until you do some cleanup.  I've seen several clients with values, in some cases large ones like you describe, left in inventory even though there's zero quantity on hand.  

The "leftover" value will continue to "roll forward" too, seeming to really mess up your average costs with no apparent reason.  So if you are using average cost, and no other culprits are readily apparent, you may need to run the Balance Quantity and Cost for Average Cost Items utility, a program Sage created to help fix the fallout that these issues with average cost left behind.  You also need to run the Recalculate Item History utility afterwards to do cleanup in other files (like the Period Posting History file, where trial balance info is kept).  There may be journal entries needed afterwards as well.  So if you go this route, make a backup company first, do the whole process in the backup company to verify what it will do, and make sure you read all the documentation about the utilities before you run them so you understand what it is going to do.  These utilities can make big changes to historical data, on hand quantities, etc.  It will clear things up if your issue is as I've described above.  But you'll want to make sure you're on a pretty current release so the problems don't continue to plague you.  

Good luck!

i have seen these before but I can't tell you how it gets created.

My usual approach to fixing it is to go to I/M Transaction Entry and do an adjustment transaction.

Do one transaction that adds in a quantity of 1 with a 0 cost.   Post it.

Then do a second transaction with a quantity of -1 and a cost equal to what you are trying to get rid of..  Post it.