I'm using Laravel 5.2 Queue Listeners and since the update from symfony/process 3.0.7 to 3.0.8 i'm getting this message alot:

'Symfony\Component\Process\Exception\RuntimeException' with message 'A temporary file could not be opened to write the process output to, verify that your TEMP environment variable is writable' in \laravel\vendor\symfony\process\Pipes\WindowsPipes.php:56

And the process closes out, now it doesnt happen all the time, just after a while.
It works fine when using process 3.0.7.

I checked sys_get_temp_dir(); and it returned the regular windows temp directory, should be ok.
To be sure i created a C:\temp folder, opened all permissions and configured it in php.ini, but it did not make a difference. I do see some files appear in this directory:
sf_proc_00.err and sf_proc_00.out, but no sf_proc_00.check file.

I am on Windows 10 x64. Let me know if you need more details.