I've not seen this before, so we would definitely need more steps to reproduce if you can come up with them.

The full stack track from your PHP error log would be useful as well.

Will provide asap

i get the same thing

Please provide the steps to reproduce

i don't know how it happens, just sometimes it shows me that error, and some times it goes away

See Contributing Bug Reports

the error apears when function "phabricator_format_local_time" in phabricator/src/view/viewutils.php, gets a $epoch var that for some reason has a decimal point, so when some sort of activity somehow manages to get a timestamp from something like pushing a commit that has a decimal point, DateTime() will throw and exception, i don't know how phabricator manages to get that decimal point there, but i recently pushed a commit and it seems phabricator gave it a timestamp of "1449419124.4675491878", so anything that displays list of my activities (including my profile page) gets this error because of the invalid time stamp. i think there should be some code to make sure the timestamp is a rounded int.

There should be a stack trace in your web server logs. We're only interested in the root issue.

I assume your install is at HEAD, correct?

2015/12/06 20:28:44 [error] 7203#0: *9085 FastCGI sent in stderr: "[2015-12-06 19:28:43] EXCEPTION: (Exception) Construction of a DateTime() with epoch '1449419124.4675491878' raised an exception. at [<phabricator>/src/view/viewutils.php:86]
arcanist(head=master, ref.master=9e78d15fc0c7), phabricator(head=master, ref.master=5b4825cf1eea), phutil(head=master, ref.master=5538909d6468)

#0 <#2> phabricator_format_local_time(string, PhabricatorUser, string) called at [<phabricator>/src/view/viewutils.php:7]
#1 <#2> phabricator_date(string, PhabricatorUser) called at [<phabricator>/src/view/viewutils.php:20]
#2 <#2> phabricator_relative_date(string, PhabricatorUser) called at [<phabricator>/src/applications/feed/builder/PhabricatorFeedBuilder.php:46]
#3 <#2> PhabricatorFeedBuilder::buildView() called at [<phabricator>/src/applications/people/controller/PhabricatorPeopleProfileController.php:251]
#4 <#2> PhabricatorPeopleProfileController::buildPeopleFeed(PhabricatorUser, PhabricatorUser) called at [<phabricator>/src/applications/people/controller/PhabricatorPeopleProfileController.php:165]
#5 <#2> PhabricatorPeopleProfileController::processRequest() called at [<phabricator>/src/aphront/AphrontController.php:29]
#6 <#2> AphrontController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:237]
#7 phlog(Exception) called at [<phabricator>/src/aphront/handler/PhabricatorDefaultRequestExceptionHandler.php:32]
#8 PhabricatorDefaultRequestExceptionHandler::handleRequestException(AphrontRequest, Exception) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:632]
#9 AphrontApplicationConfiguration::handleException(Exception) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:242]
#10 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicati

pulled latest version still same

Feed Story's getEpoch() is doing some serious magic: https://secure.phabricator.com/diffusion/P/browse/master/src/applications/feed/storage/PhabricatorFeedStoryData.php;20e6a4200dbc72760ea5de4eb15053bc1b2c8dac$41

@nnnn20430: Is your system 32 or 64 bits? Do you have the bc extension? Do you have any database issues (Visit "config" tab).

@avivey: 32bit, yes, no
and the error just went away...

Probably can try to install bc and report back if you still see it. What MySQL version are you running?