Allowing access, 'My Files' won't open

[Ana R]

Each time I try to create a folder pair to sync with my Chromebook, Dropsync asks me to grant access to My Files to create a local file on device. 

I have repeatedly agreed to this action and then nothing pops up to allow me to select and create the second folder in my pair, thus there is nothing to sync. 

I tried uninstalling and re-installing the Dropsync app and looked in my Chromebook settings for an option to grant access for this app but had no luck. 

Any suggestion would be greatly appreciated. 
Thanks!