1. The ordinary causes come first
Before suspecting anyone, rule out the dull explanations. Material issued to a site by somebody being helpful and not written down. Breakage removed from the shelf and never recorded. A short delivery accepted without a claim. An item billed at the wrong rate. A return restocked twice. A unit conversion set up wrongly so every sale of that item is out. Those account for the overwhelming majority of differences, and each is fixable.
2. Close the day, every day
A cash book reconciled monthly tells you there is a difference and nothing about where it came from. Reconciled every evening, it tells you which day and usually which transaction. Record receipts by mode, record anything paid out of the drawer, and compare cash against what is physically there. Shops that adopt this stop having unexplained differences within a few weeks — not because anyone was caught, but because mistakes get found while they are findable.
3. Individual logins, and say why
Sharing one password means nothing is attributable and the arrangement survives whoever leaves. Individual logins with only the permissions each person needs make the audit trail meaningful. Tell your staff the trail exists and explain why — people are more careful when entries are attributed, and nobody resents a control that was explained on day one rather than introduced after an accusation.
4. Keep three permissions to yourself
Seeing purchase rates, editing or deleting a saved bill, and changing item rates. The first is your margin, the second is where a shortfall gets covered up, and the third is how a price quietly drifts. Staff can be allowed to discount up to a limit rather than freely, which handles ordinary counter negotiation without leaving it open.
5. Control what leaves the godown
Nothing should go out without a bill or a recorded delivery, and that has to be a rule rather than a preference. Most godown differences in material shops are genuinely sent material that nobody wrote down. Once the rule holds, a difference that remains is information rather than noise, and it is worth investigating.
6. If something is genuinely wrong
With the ordinary causes eliminated and daily reconciliation in place, a persistent difference narrows to a person, a shift or a product very quickly. At that point you have dates, amounts and attribution rather than a suspicion. Handle it on the evidence and privately. The controls above are what make that possible; without them you have only a feeling, which is the worst basis for an accusation.