I had some troubles lately while running some ipython notebooks in windows, because of .ipynb files having long path string. Actually, I think this is a windows issue, since it occurs in others softwares, like visual studio.

However, the error message presented by Jupyter wasn't really useful at all, since the path was so long that it could not fit in just one line. I was able to see the error message by inspecting the html element using google chrome, and just after that, I have realized that the problem was actually the long path. Probably, it would be more useful if this message is presented in a multi line box.

The full error message, which I was able to retrieve only by inspecting the html element, was:

'Unexpected error while saving file: Documents/xxxx/xxxxxxl/Online Courses/Specializations/Coursera - Build Intelligent Applications/2 - Machine Learning - Regression/Week 1 - Simple Regression/Code Files/Assignment/week-1-simple-regression-assignment.ipynb [Error 206] The filename or extension is too long: u'C:\Users\xxxxx\Documents\xxxx\Professional\Online Courses\Specializations\Coursera - Build Intelligent Applications\2 - Machine Learning - Regression\Week 1 - Simple Regression\Code Files\Assignment\week-1-simple-regression-assignment.ipynb_4z9ts'

Yeah, this path is insanely long... :)