Thanks for reporting. I am sorry for the bug. it’s my fault, the string type has only been introduced recently in matlab and I forgot to add a test for the version. Temporary quick fix is to replace:
if ~isoctave() && isstring(b) && length(b)>1 && isvector(b)
by
if false
on line 52, or you can safely remove the block.
The fix, with a proper test on matlab’s version, will be published in 4.5.3.
The patched proposed by @jpfeifer two days ago has been merged in 4.5 branch. Unfortunately I missed the patch before the release… It will be in the next one (November). You can replace the isfile.m by this version (in the matlab/missing/isfile folder).