[SM-USERS] User prefs and other data files wiped out during server reboot

[Alan in T. <squ...@fi...>]

SquirrelMail 1.4.22
Applied patch to functions/mime.php that is included in 1.4.23svn
PHP 5.2.9, SuPHP module, Zend Optimizer
Dovecot 1.1.19 (in a cPanel release), but uses some Courier NAMESPACE settings such
as prefix = INBOX.
Capabilities: * CAPABILITY IMAP4rev1 SASL-IR SORT THREAD=REFERENCES MULTIAPPEND
UNSELECT LITERAL+ IDLE CHILDREN NAMESPACE LOGIN-REFERRALS UIDPLUS LIST-EXTENDED
I18NLEVEL=1 QUOTA STARTTLS AUTH=PLAIN AUTH=LOGIN
Maildir mail storage format
Mail is stored in /home/webaccountname/mail/mailusername/
Apache 2.0.63, cPanel virtual web hosting account
ESMTP Exim exim-4.87-5.cp1156
IMAP Server Address: 127.0.0.1
SMTP Server Address: 127.0.0.1
Server side sorting is enabled
Server side thread sorting is disabled
Allow editing of identities: Yes
Allow editing of full name: Yes
SquirrelMail access via SSL (https) for entire session
Browser: usually IE9, plus testing on others
User login with full e-mail address, e.g. al...@my...
Many plugins, including: Auto Complete; Folder Synch; Select Range; etc.
Compatibility plugin 2.0.16
SquirrelMail configtest: pass

Hello:

Today when I was logged into my own user account in my SquirrelMail installation,
the server was rebooted. That wiped out my user prefs file and several other related
files for signatures and some plugin data.
e.g.

us...@do...ef
us...@do...g
us...@do....s1
us...@do....s2
us...@do....words

etc.

The filenames still exist in that directory, but the contents have been somehow
wiped out.
The last time this occurred, a web server support tech had killed all server
connections to stop a spammer. I was logged into SquirrelMail at that time. He
thinks that because SquirrelMail couldn't properly access those files, or because
they were in use, the contents got wiped out and became zero bytes.

Is there any way to prevent this from happening?