When you add a new user (in vTiger CRM v5.4.0) then it is possible that you can select a language setting e.g. “English GB” that has a non-existent translation file. If you do this then that user will get the error message,

Sorry! Attempt to access restricted file.

on a blank screen after they log on. They will stay in this state forever until the logon cookie is removed or the language file is created. The language files exist under the path,

include/language

To fix this you must either

• upload the correct language file or
• use another browser and go in as a working user e.g. admin and reset the language to a known working language e.g. English US or
• clone the include/language/en_us.php to the correct file name e.g. en_gb.php. To identify what file is needed you can add a print_r($filepath); to the include/utils/CommonUtils.php file function checkFileAccessForInclusion() around line 2817 onwards but before the die(). You can’t keep that debug code in place as the ajax javascript breaks but it will tell you what language filename it is after.

That should solve this first-day-of-use problem.