unknown error: failed to write prefs file

Question

I keep getting the error while running functional tests using runner with following: -selenium 2.44 -Chrome Driver -Windows Server 2008 R2 Enterprise

Error Description: Listening on 0.0.0.0:7000
Starting tunnel...
UnknownError: [POST http://test.com/wd/hub/session / {"de
siredCapabilities":{"browserName":"chrome","name":"tests/intern","idle-timeout":
60,"selenium-version":"2.44.0"}}] unknown error: failed to write prefs file
(Driver info: chromedriver=2.12.301325 (962dea43ddd90e7e4224a03fa3c36a421281ab
b7),platform=Windows NT 6.1 SP1 x86_64) (WARNING: The server did not provide any
stacktrace information)
Command duration or timeout: 1.06 seconds

Anyone have ever come across such issue? How do i fix this? Suggestions please

Answer 1

It can be caused by executing ChromeDriver in parallel. Other errors as "failed to write first run file" or "cannot create default profile directory" may happen in that case.

My solution was to specify option user-data-dir. Two concurrent Chromedriver should not use same user data directory.

chromeOptions.AddArgument("--user-data-dir=C:\\tmp\\chromeprofiles\\profile" + someKindOfIdOrIndex);

You can of course change the path for whatever you want :)

Answer 2

This issue occurs if C drive disk runs out of space.The best solution to clear temp files.This solution worked for me.

Open Run command

2.Type % tmp%

3.Click on OK

4.Select all files.Delete all the files permanently.

Answer 3

I've recently had the same issue. The problem was caused by full C drive. Apparently chromedriver needs some space in C drive (or the drive where chrome binary file is located) to create temporary profile files and so on.

One of the solutions could be to move chrome installation to some other drive. You could use mklink command in command line window.