Under some circumstances, a page request can result in nothing more than
a blank page. In most cases, this happens after the installation of a
plugin, but it can happen elsewhere as well. This problem is typically caused
by fatal PHP errors that are simply not being shown on screen.
You can find those errors by looking in your web server log file. The
location of that file will be different on some machines, but one
example is /var/log/httpd/error_log.
Alternatively, you can tell PHP to display the errors on screen in one
of a few ways described below (remember to turn them off again if you
are doing this in a production environment):
Change the error reporting settings in php.ini (remember to
restart the web server after you make changes to php.ini):
Change the error reporting settings just for SquirrelMail by
adding the following lines into an .htaccess file in the
main SquirrelMail directory (this is an Apache web server
feature that also requires that you have at least
"AllowOverride Options" in the <Directory>
section that applies to your SquirrelMail installation
within the Apache configuration file).
php_flag display_errors On
php_value error_reporting E_ALL
Note that if you still have trouble seeing errors on screen, make sure
you have not overridden the error reporting settings in your Apache
configuration file or in another .htaccess file or custom SquirrelMail
Some more common causes of blank pages are:
You installed a new plugin but forgot to install one of
its dependencies (such as the
Compatibility plugin) or apply a required patch.
Please carefully consult all the documentation files that
came with your new plugin, including its README and
You are attempting to view a folder with a very large number
of messages in it (perhaps as many as 10,000). In this case,
you may hit the maximum PHP execution time limit or maximum
memory limit. If you find such errors, you may want to
You have installed SquirrelMail for the first time and it does
not work at all - even the configuration test page and the login
page come up blank. This can be caused by the lack of session
support in PHP (which SquirrelMail requires). See the
PHP session extension installation manual.
If you are able to access your IMAP server using means other than
SquirrelMail (that is, if your server's IMAP or IMAP-SSL ports are
available from your location), it is recommended that you use a dedicated
migration tool, such as
IMAPCopy. IMAP copying/migration tools are available for various
platforms, so if neither of these two fits your requirements, use a search
engine to find something to match your setup.
If you are able to use another IMAP client (such as
Thunderbird) to access
mail on your servers, you can add both the new and old accounts to it
and drag and drop messages between the old and new accounts. Note that
this requires each user to set up and migrate their own messages - you
cannot migrate multiple user accounts automatically using this method.
If you are migrating away from a POP3 server, you can use the Mail Fetch
plugin (bundled with SquirrelMail). It'll transfer mail from your POP3 inbox
to your SquirrelMail installation, but it won't handle folders. Note that
this requires each user to set up and migrate their own messages; if you
need to automate the process for multiple users, use another tool or create
your own script to add the needed SquirrelMail settings for the Mail Fetch
plugin to each user's SquirrelMail preferences.
If you're migrating away from SquirrelMail you can use the
plugin to download mails from the server, but there might not be an easy way
to upload those mails to the new server.
When using tools other than SquirrelMail, you'll probably need to make sure
that the ports needed to access the servers are open. The system
administrator may need to help you if you don't have the access or ability
to open them yourself (or if any of the systems you are working with use
any non-standard ports).
The standard ports to use for clients and/or migration tools are: