Laravel 5.4 fopen(): Filename cannot be empty

We had this problem with Internet Information Services (IIS) for Windows® Server. And only thing needed was - permission for C:\Windows\temp because it is set as upload_tmp_dir in php.ini for php7.

My case with Laragon 4.0.12 on Windows 10.

The problem was that upload_tmp_dir=... in my php.ini had not set needed permissions.

If this setting is commented the value should be the default windows temp directory (C:\Windows\Temp you can check your permissions for it).

The solution - I changed it to:

upload_tmp_dir = "C:\Users\{my_user}\AppData\Local\Temp" 

in order to avoid messing up with changing permissions.

Restart the server after the change to take effect.

Another settings in php.ini to consider:

upload_max_filesize = 
max_file_uploads = 

Also following php extensions are needed to be enabled: exif, gd2