Pix2PixHD Hanging at 'create web directory'

[iamekm]

Hi there,
I'm running Pix2PixHD_Next_Frame_Prediction.ipynb in Google colab, following the link to 'open in colab' on this page: https://github.com/dvschultz/ml-art-colabs/blob/master/Pix2PixHD_Next_Frame_Prediction.ipynb
Everything works well until I start 'Initial Training' where it hangs at 'create web directory' & no epochs appear beneath.
Apparently I'm connected to a Tesla K80 GPU. Tried restarting the runtime a few times and it always hangs at the same place. I left it a good 30 mins or more, and the dataset is only ~350 images at 1280x736 pixels (which seemed to work well when I tried this a few months ago!) It gets as far as making the 'web' folder which contains 'loss_log.txt' and 'opt.txt' - but nothing else.