Cannot export sprite on windows 8.1 about alferd-spritesheet-unpacker HOT 1 OPEN

Thanks for logging the issue. Unfortunately this is a known issue I've been struggling to fix because I can't replicate it. If you are able to debug it I'd be most grateful or you could try the below workaround.

from the FAQ:

When I click the 'Export selected' button Alferd Spritesheet Unpacker just freezes, what the cuss?

This is weird but happens on some people's PCs. The error occurs because ASU is trying to ask you which folder you'd like to export the sprite frames to but for some reason the operating system is preventing the 'select folder' form from showing. To solve this (works for most people) click the 'Options' button and then untick the 'Prompt for Export Folder' check box. Now ASU will just export the frames to whatever location you've entered in the long text box on the main form. See this gamedev.stackexchange.com post for more details http://gamedev.stackexchange.com/questions/34055/how-can-i-unpack-a-sprite-sheet-into-multiple-images/38560#38560/.

from alferd-spritesheet-unpacker.