MikroTik

Hi on my dude every now and then my network devices seem to disappear leaving a little grey device with unknown in brackets. Does anyone know why this might be happening?
Example
- 192.168.1.x jane -to- (Unknown)

Any help will be much appreciated

Can you post any screenshot of your problem?

Yes next time it happens I will post a screen shot, but basicly its like a device that you cant get the settings for and its grey like when you dont have any services to a device.