What do you mean by external? Hmmm if this a hard drive maybe you should check it to another pc/laptops or maybe your enclosure was not working. Worst case is your external is busted.
Baka nga nasira lang yung enclosure niya. Pag ayaw na talaga gumana pwede mo baklasin tapos kunin mo hdd sa loob then test mo via sata cable sa pc kung mareread. Sakin dati Bigla nalang ayaw gumana pero na reread naman sa pc via sata cable. Binilan ko lang ng bagong enclosure. Ayun ginagamit ko pa naman ngayon.
Sir try mo tingnan sa Disk Management kung lumalabas ba ang external mo pagsinasaksak mo.
Pag nakalist siya, kailangan mo reformat siya gamit any recovery application, tulad ng "i care data recovery" para ma back-up mo ma files mo