No it just means that the mouse is picking up vibration from using your PC, also some optical mice don't like certain surfaces and can be erratic. Leaving it upside down until it is needed just means that it won't affectyou whilst you are using JAWS because there is nothing to track. Regards. Tristram Llewellyn Sight and Sound Technology Technical Support www.sightandsound.co.uk Mail: Tristram: tristram.llewellyn@xxxxxxxxxxxxxxxxxxx Technical: Support@xxxxxxxxxxxxxxxxxxx General - info@xxxxxxxxxxxxxxxxxxx Phone: Support line: 0845 634 7979 Sight and Sound Technology Limited is a company registered in England and Wales, with company number 1408275. Sight and Sound Technology Welton House North Wing Summerhouse Road Moulton Park Northampton NN3 6WD VAT Number - GB 860 2121 66. ** To leave the list, click on the immediately-following link:- ** [mailto:jaws-uk-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** jaws-uk-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:jaws-uk-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** jaws-uk-request@xxxxxxxxxxxxx with the Subject:- faq