This report doesn't look to include reproduction information.

For me seems to be quite good the information provided, but I try to explain myself with more details:

• Firstly, I have updated phabricator, arcanist and arcanist to latest versions (detailed above)
• Then, I try to make a revision while executing command arc diff
• Error is displayed

PHP Fatal error: Call to undefined function id() in <dir>\libphutil\src\moduleutils\PhutilBootloader.php on line 93

Thanks in advance

We need to know how to reproduce bugs in order to fix them. Please take the time to give us all information needed about your environment so we can reproduce the bug. Id() missing means something is dramatically wrong with your installation, as no part of Phabricator is expected to run without access to libphutil and its functions.

The current steps are incomplete for us to reproduce the bug.

Thanks chad. I will check if there is a problem with the installation and let you know.

Definitely there was a problem with the installation, for some reason the files got corrupted and downloading a fresh installation solved the problem.

Thanks,
Juan