Comment 16 for bug 707287

hi all
I have the same problem that Kyle,

1. a product had a bad UOM
2. an inventory adjustment
3. mrp run into exception "UoM Conversion Product from m to Default UoM PCE is Not possible As They Both Belong to Different Category!."

Then our first problem was to figure out what was the product that raises this exception. because m and PCE are harcoded in the string. I added the following code on product.py line 144 before the raise statement, to get more information:

sys.stderr.write('conversion desde %s hasta %s no es posible cantidad %s' % (from_unit.name, to_unit.name, qty))
sys.stderr.flush()

After much research we discovered the product that generated the problem and correct the UOM on the product but the exception did not disappear.

when I read your comments I discover that the inventory adjustment was the blame, then I removed the product from BOM recreate it with the correct UOM and after that adjust the inventory, then put the corrected product in the BOM. This NOT solved the problem. Just moved the error to the next product.
The only difference with Kyle's scenario is that I've never had installed magento

I am in full agreement with what was said by Kile, the bug is very serious.
please see also Bug #716705 Product UoM conversion error needs definition

I hope this helps