Forward voltage of a diode
Saying that a diode has a forward drop of any single voltage value is to miss the bigger point about diodes. &quot;One size doesn't fit all&quot; when it comes to properly understanding diodes.
A diode is said to have a forward drop of about 0.7 volts when it is conducting about 10 mA. If it were conducting 1 mA, a good rule of thumb is to assume the forward drop has reduced by 100 mV to 0.6 volts.

If it were conducting 0.1 mA then the forward drop would be approximately 0.5 volts.

At a current of 0.01 mA the forward drop would be about 0.4 volts etc etc..


So, you have a simulated circuit and maybe the voltmeter showing 9.345 volts has some kind of internal simulated resistance that draws a tiny bit of current that causes the diode forward volt drop to be 0.179 volts. Maybe it simulates the standard impedance of a multimeter (10 MΩ).
If it is 10 MΩ then, with 9.345 volts across it, the current is 0.9345 μA or about 1 μA. By my simple reckoning above, the forward volt drop would be a shade under 0.3 volts so, it's not a mile off and remember, I wasn't specific about  the type of diode. I expect that if I found a good data sheet for the 1N4001 diode that you used, I might be able to tweak my general rule of thumb to be more indicative of what a 1N4001 exhibits.
Of course, if you think that your simulator has a voltmeter with a different input impedance then you can prove this for yourself by connecting it to a 1 volt supply in series with a resistor and increase the resistor in value until the meter reads 0.5 volts.