Troubleshooting

Things that look wrong in inventory, and what is usually behind them.

Quantities

The stock figure is not what I expect.: Check which revision the part details dialog is on. Stock is held per revision, so ten on one revision and none on another are both correct answers to different questions.
Stock exists but I cannot find it on the Location tab.: It is probably unassigned, meaning it is held but never placed. The unassigned figure is at the top of the tab. Use Assign stock to give it a home.
Available is lower than total stock.: Some of it is borrowed or scrapped. Borrowed stock is still yours but is out with someone; scrapped stock is written off. Both are excluded from what you can use.
Assign offers fewer units than I have.: You can only assign unassigned stock. Anything already in a location has to be relocated instead. For a lot tracked part the limit is per lot, so check which lot is selected.

I cannot pick the location I want.: Choose the location type first. The type decides which fields appear, and until one is chosen there is nothing to fill in.
The dialog turned into a scrap form.: You picked a location type of SCRAP. That is how scrapping works, and it is a write-off rather than a move. See Scrap stock.
I cannot type a quantity for a serialised part.: The quantity follows from the serial numbers you pick, because Partix has to know which physical units moved. Select the units instead.

Serial numbers do not match the stock figure.: Use Sync Serial Numbers to Stock on the Location tab. Check the physical stock first, because sync makes the record self consistent rather than correct. See Syncing serial numbers.
A cycle count is asking which units are missing.: Expected, on a serialised part counted short. "Three fewer" is not enough detail when each unit is identified, so pick the specific numbers.
I cannot see lot fields on a part that has lots.: Lot selection only appears for lot tracked parts, and only in screens that move stock.

A part has shown as borrowed for months.: Almost always a return nobody recorded. Open Borrowed on the row and use Mark as Returned. Nothing clears an overdue return on its own.
Stock went out and I cannot find who has it.: The Borrowed dialog names the person and project for each borrow, along with the estimated return date given at release.

The calculated cost is not what I paid.: Read the costing rule alongside the active lot. Under FIFO the cost comes from your oldest batch, which may be much older than your last order. See Costing.
Product costs changed and nobody edited the product.: A part's costing rule or its active lot may have moved. Rolled up cost in a BOM is built from part costs, so a change here reaches every product using the part.

Note the part, the revision, what you were doing and what you expected. Send that to your Partix contact.