Here is the output from one of the older mangoes that DOES exhibit the problem:

mango@mangoES3047:~$sudo tail -n 50 /var/mail/mail
[sudo] password for mango:
Envelope-to: root@mangoes
Delivery-date: Thu, 13 Jun 2019 17:15:02 +0800
Received: from root by mangoES3047 with local (Exim 4.84)
(envelope-from root@mangoes)
id 1hbLp0-0003k9-7R
for root@mangoes; Thu, 13 Jun 2019 17:15:02 +0800
From: root@mangoes (Cron Daemon)
To: root@mangoes
Subject: Cron root@mangoES3047 /usr/sbin/systemInfo/getAll
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=root>
Message-Id: E1hbLp0-0003k9-7R@mangoES3047
Date: Thu, 13 Jun 2019 17:15:02 +0800

• Dir=/opt/info/
• LogFile=systemInfo-new.txt
• Together=/opt/info/systemInfo-new.txt
  ++ uname -m
• arch=armv7l
• [[ armv7l == \a\r\m\v\7\l ]]
  ++ mount
  ++ grep 'on / type'
  ++ awk '{print $1}'
• DiskName=/dev/mmcblk0p2
• echo '########DISK##########'
• echo -ne 'Disk Name: '
• echo /dev/mmcblk0p2
• echo -ne 'Disk Total Size: '
• df -m /
• tail -1
• awk '{print $2}'
• echo -ne 'Disk Space Used: '
• df -m /
• tail -1
• awk '{print $3}'
• echo -ne 'Disk Space Left: '
• df -m /
• tail -1
• awk '{print $4}'
• echo -ne 'Disk Percent Used: '
• df -m /
• tail -1
• awk '{print $5}'
  /usr/sbin/systemInfo/getAll: line 10: /usr/sbin/systemInfo/timeAlive: No such file or directory

mango@mangoES3047:~$

I tried running this frequently for a minute or so - it looks like an entry is added every 30 seconds.

And here is the output for a new Mango that does NOT exhibit the problem (date is old):
mango@mangoES3546:/etc/rc1.d$sudo tail -n 50 /var/mail/mail
[sudo] password for mango:
Return-path: root@mangoes
Envelope-to: root@mangoes
Delivery-date: Fri, 30 Mar 2018 12:36:32 -0600
Received: from root by mangoes with local (Exim 4.84_2)
(envelope-from root@mangoes)
id 1f1yt6-0004zh-CB
for root@mangoes; Fri, 30 Mar 2018 12:36:32 -0600
From: root@mangoes (Cron Daemon)
To: root@mangoes
Subject: Cron root@mangoes (sleep 30; [ -x /usr/sbin/systemInfo/cronRunner ] & & /usr/sbin/systemInfo/cronRunner);
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=root>
Message-Id: E1f1yt6-0004zh-CB@mangoes
Date: Fri, 30 Mar 2018 12:36:32 -0600

• Dir=/opt/info/
• LogFile=systemInfo-new.txt
• Together=/opt/info/systemInfo-new.txt
  ++ uname -m
• arch=armv7l
• [[ armv7l == \a\r\m\v\7\l ]]
  ++ mount
  ++ grep 'on / type'
  ++ awk '{print $1}'
• DiskName=/dev/mmcblk0p2
• echo '########DISK##########'
• echo -ne 'Disk Name: '
• echo /dev/mmcblk0p2
• echo -ne 'Disk Total Size: '
• df -m /
• tail -1
• awk '{print $2}'
• echo -ne 'Disk Space Used: '
• df -m /
• tail -1
• awk '{print $3}'
• echo -ne 'Disk Space Left: '
• df -m /
• tail -1
• awk '{print $4}'
• echo -ne 'Disk Percent Used: '
• df -m /
• tail -1
• awk '{print $5}'

mango@mangoES3546:/etc/rc1.d$tail -n 50 /var/mail/mail

The cron job looks OK:

mango@mangoES3047:/etc/cron.d$more system-info

Regular cron jobs for the system-info package

• • • • • root [ -x /usr/sbin/systemInfo/cronRunner ] && /usr/sbin/systemInfo/cr
          onRunner >/dev/null 2>&1;
• • • • • root (sleep 30; [ -x /usr/sbin/systemInfo/cronRunner ] && /usr/sbin/sy
          stemInfo/cronRunner) >/dev/null 2>&1;
          0 0,6,12,18 * * * /usr/sbin/systemInfo/packages;
          mango@mangoES3047:/etc/cron.d$

I compared this to the file on the newer mango, and the only difference I can see is the addition of 'root ' before the path in the last line.
ie, it's "#0 0,6,12,18 * * * root /usr/sbin/systemInfo/packages;

Shall I try adding this?

Can you share the output of tail -n 50 /var/mail/mail ?

Also perhaps can you ensure the /etc/cron.d/system-info cron job is directing its stdout and stderr to /dev/null, > /dev/null 2>&1 ? This should have occurred in updating the MangoESConfiguration module to the versions Joel mentioned (or later versions).

I checked the /var/mail/mail file and that one was the problem. I deleted the file and now it's ok.

Thank you!

Here are two relevant release notes from the MangoES Configuration Module:

Version 3.3.1
Fixes to prevent /var/mail/mail file from growing, delete that file if present
Version 1.2.1
Fix for inodes filling /var/spool/exim4/input from /etc/cron.d/system-info cron commands