Error: EPERM: operation not permitted, open

{ Error: EPERM: operation not permitted, open 'C:\Users\Vivek Sharma\apps\testAp
p\www\assets\imgs\Thumbs.db’
errno: -4048,
code: ‘EPERM’,
syscall: ‘open’,
path: ‘C:\Users\Vivek Sharma\apps\testApp\www\assets\imgs\Thumbs.db’ }

[03:09:32] deeplinks started …
[03:09:32] deeplinks finished in 110 ms
[03:09:32] ngc started …
[03:09:59] ngc finished in 26.71 s
[03:09:59] preprocess started …
[03:09:59] preprocess finished in 3 ms
[03:09:59] webpack started …
[03:11:33] webpack finished in 94.64 s
[03:11:33] uglify started …
[03:11:33] sass started …
Error: EPERM: operation not permitted, open ‘C:\Users\Vivek Sharma\apps\testApp
www\assets\imgs\Thumbs.db’
(node:14288) PromiseRejectionHandledWarning: Promise rejection was handled async
hronously (rejection id: 1)
[03:11:36] sass finished in 2.99 s
[03:11:36] cleancss started …
[03:11:40] cleancss finished in 3.62 s
[03:12:08] uglify finished in 34.76 s

This error occurs when trying to build apk. using ionic cordova build android --release --prod

ionic v-3.19.0
cordova -v-8.0.0
node -v-8.8.3
npm -v-5.3.0

WINDOWS 8.1 64 bit.

please help