In this thread I tried to upload both an HTML file and a text file, and received the following error message:
Error Message:
upload_unable_to_write_file
I was able to upload a zip file successfully, though.
I expect that this is because these two file types aren’t allowed to be uploaded, in which case the bug is that the error message isn’t being generated properly, to inform the user of the restriction in file type. If these files aren’t restricted (in the case of text files I can’t see any reason why they should be treated so), then there’s an error in the upload feature itself.
In the case of restrictions due to file types, it would further help if the user could be notified in advance of what types of files are allowed for uploading.