I am trying to find a fault on a multilayer board currently. I use mostly my multimeter in buzzer mode and came across such a situation. When i measured a 1kohm resistor in buzzer mode it didn't beep as expected and gave the resistance as 900ohm. When i switched to resistance measuring mode i read 1kohm. Consistent.But the weirdness came into scene when i tried to determine where the base resistor of an npn is being drived from. I began my search by contacting one of the probes to the one end of the resistor in buzzer mode. Then visited all the vias and devices over the board for the other end. I couldn't locate it; possibly an open circuit. But i measured around 500ohms at some parts of the board. When i checked those parts in resistance measuring mode i read 100kohm.
So if i summarize ;

when i measure a resistor of 1kohms ;

1. in buzzer mode i read 900ohms
2. in resistance measuring mode 1kohms.

When i try to locate a route with a floating end (possibly an open circuit);

3. in buzzer mode i read 500ohms

4. in resistance mode i read 100kohm.

What could be the possible reason for this conflicting measurements?