Title: Invalid argument Error after installation Last modified: August 20, 2016 --- # Invalid argument Error after installation * [drmks24](https://wordpress.org/support/users/drmks24/) * (@drmks24) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/) * Hello, * I received a strange error at the backend and at the frontend as well which s: * Warning: Invalid argument supplied for foreach() in /var/www/virtual/mydomain/ wp-includes/class-wp-admin-bar.php on line 353 * What does this means and how can I fix this? * Here are some screenshots: * [http://img526.imageshack.us/img526/2020/wperror02.jpg](http://img526.imageshack.us/img526/2020/wperror02.jpg) * [http://imageshack.us/a/img201/1893/wperror01.jpg](http://imageshack.us/a/img201/1893/wperror01.jpg) * [http://imageshack.us/a/img69/1812/wperror03.jpg](http://imageshack.us/a/img69/1812/wperror03.jpg) * Thanks for your help! Viewing 10 replies - 1 through 10 (of 10 total) * [esmi](https://wordpress.org/support/users/esmi/) * (@esmi) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392331) * Have you tried: * – deactivating **all** plugins to see if this resolves the problem. If this works, re-activate the plugins one by one until you find the problematic plugin(s). * – switching to the default theme to rule out any theme-specific problems. * – [resetting the plugins folder](http://codex.wordpress.org/FAQ_Troubleshooting#How_to_deactivate_all_plugins_when_not_able_to_access_the_administrative_menus.3F) by FTP or PhpMyAdmin. Sometimes, an apparently inactive plugin can still cause problems. * – re-uploading all files & folders – **except** the wp-content folder – from a **fresh** download of WordPress. Make sure that you delete the old copies of files & folder before uploading the new ones. * Thread Starter [drmks24](https://wordpress.org/support/users/drmks24/) * (@drmks24) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392357) * Thanks for the quick reply but none of this will fix the problem because it is a fresh WP install. * – there are no active plugins – re-uploading a fresh download wordpress rar- file & uploading the files again after deleting all files except the wp-content folder doesn’t work – switching the theme back to the standart one doesn’t help( the error was also displayed before I’ve installed the theme) * Any other suggestions? * [esmi](https://wordpress.org/support/users/esmi/) * (@esmi) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392360) * I’d still argue that you have a corrupted core file. * Thread Starter [drmks24](https://wordpress.org/support/users/drmks24/) * (@drmks24) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392382) * I think so too but what else can I do then downloading the WP 3.5 rar-file again and replace the class-wp-admin-bar.php file? * I’ve downloaded it from this source: * [http://wordpress.org/download/](http://wordpress.org/download/) * I tried the zip-file and the tar.gz-file but the error is still there! * [esmi](https://wordpress.org/support/users/esmi/) * (@esmi) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392383) * The download is fine for me. No corrupted files. All I can suggest is that you try again. * Thread Starter [drmks24](https://wordpress.org/support/users/drmks24/) * (@drmks24) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392394) * Nothing happens after redownloading the rar-file over and over again so I just deleted the some code from line 353 from the class-wp-admin-bar.php and the error- message is gone. * Does anyone knows if this piece of code is important? * children as $group ) { $this->_render_group( $group );}? > * [esmi](https://wordpress.org/support/users/esmi/) * (@esmi) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392415) * Every line in WordPress core files is important. * [Tony](https://wordpress.org/support/users/antonioliscidini/) * (@antonioliscidini) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392500) * I have the same error after the installation! * Thread Starter [drmks24](https://wordpress.org/support/users/drmks24/) * (@drmks24) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392502) * Today I found out that the problem is caused by our server. The server is a few years old and wie tried to work with a external php.protocol that caused the errors because of a wrong or high security standart. Finally we decided to move our website to a new and more up to date server. * Maybe this information will help other ppl with the same problem! * [Tony](https://wordpress.org/support/users/antonioliscidini/) * (@antonioliscidini) * [13 years, 3 months ago](https://wordpress.org/support/topic/invalid-argument-error-after-installation/#post-3392503) * I have found this solution add the following code at the beginning of your wp- config.php file after