On C5_W4_A1_Transformer_Subclass_v1 I get an error: “Permission denied: W4A1/C5_W4_A1_Transformer_Subclass_v1.ipynb”.
I submitted the assignment and I got 0 grade; when I opened it again it was nothing saved, all was lost.
Hi Im having the same issue, did you get it solved?
They are aware of the issue. Been a problem over the weekend so hopefully sorted in next day or two. Make sure to copy and paste your code to a notepad on your PC so you can copy it back in when back working as save and checkpoints may be problematical.
Many learners told us that this workaround can help them get a new copy of assignment that has the permission to save work and submit work as usual. This is something you could try to keep moving on.
Raymond
It worked for me, I renamed the W4A1 folder to W4A2, created new W4A1, got latest version (Help → Get Latest Version), and completed the work, the course, and specialization. 
Thank you.
I have the same experience and same error you are seeing for W3A2 even after the folder rename work around.
The solution of copying the notebook to a different folder worked. Thank you