Hi,
I had a look at this and a fix is currently awaiting review (AP-18190 for internal reference).
I did not really have the chance to think much about finding a workaround for the intermediate time. Here’s one thing that worked for my simple test case. However, you may run into authentification issues or other problems.
The idea is to create a symbolic link to the problematic folder s.t. the link name does not contain spaces.
In the windows command prompt (you may need admin privileges), you can create a symbolic directory link in the current working directly with mklink /d link-target-name "\\host\path\files to read".
This creates a new link called link-target-name that points at the shared directory. You can then set the node to read from this path, e.g. C:\Users\Knime\Desktop\files-to-read-link instead of \\host\path\files to read.
Best Regards,
Ben