Sandisk Connect Flash Freezes

I have now also upgraded to iOS9, hoping that would fix it.

I opened maybe a dozen files, one after the other in one folder, then selcted another folder, and a file from it, and all I have is a grey sandisk screen.

I can go back to select another pdf, but still get the same grey screen.

any help, please. the pdfs are music files and I need to use this ipad for my performance.

i am getting desperate…