VirtualBox Guest Additions not working in Lubuntu 17.04 – Solved


Host OS: Windows 10 x64
VirtualBox Graphical User Interface
Version 5.1.26 r117224 (Qt5.6.2)

Guest OS: Lubuntu 17.04



I manually installed VirtualBox Guest Additions from VBOXADDITIONS_5.1.26_117224 ISO and restarted the guest.

The bidirectional clipboard and the drag and drop still not working.


Installation of Guest Additions from Ubuntu repository.


sudo apt-get install virtualbox-guest-dkms virtualbox-guest-utils virtualbox-guest-x11

Because I didn’t uninstall the ISO version, the setup process it asked me if I want to use the maintainer version or the latest version. Personally I chosed Y for the maintainer version. Here is a sample:

Setting up virtualbox-guest-x11 (5.1.22-dfsg-0ubuntu1.17.04.1) …

Configuration file ‘/etc/X11/Xsession.d/98vboxadd-xclient’
==> File on system created by you or by a script.
==> File also in package provided by package maintainer.
What would you like to do about it ? Your options are:
Y or I : install the package maintainer’s version
N or O : keep your currently-installed version
D : show the differences between the versions
Z : start a shell to examine the situation

It works! The above text was copied from clipboard directly from Guest OS Lubuntu 17.04 in Windows 10 host OS.

10 Ways to transform PDFs in Online Publications

The purpose of this article is to explore solutions that allow us to transform Adobe PDF files into a page turning digital book or magazine.

The main features that we are looking are:

  • multi-platform: desktop, tablet, mobile etc.
  • page-turning or flipping feature

Without being exhaustive, here is a list of the most popular solutions for online publications with links and screenshots.













Categories Web

cPanel not starting with Internal Server Error – fix

The problem:

All websites are down with Internal Server Error 500


Cpanel wasn’t loading with the following error:

Internal Server Error


Can’t fork: Cannot allocate memory at /usr/local/cpanel/Cpanel/SafeRun/ line 40.
cpsrvd/ Server at

How I fixed it?

First of all I was trying to increase this limit by searching for “Max cPanel process memory” in:
“WHM Home » Server Configuration » Tweak Settings”

It was already over 512MB, the default value of 768MB. I increased to 1024MB. The Cpanel restart was unsuccessful.

As last resort I run the following commands:

/scripts/upcp –force

service cpanel restart

The first command will upgrade cPanel even if you got latest version of cPanel, in order to rule out any update inconsistencies.  Depending on the server configuration, this may run for about 10 minutes.

The second command will restart cPanel.

I hope that was helpful for you.


How to sync Microsoft Outlook with Google Calendar and other CalDav Calendars

For this purpose we need to use Outlook CalDav Synchronizer.

Here are the features and description from developer:

Free Outlook Plugin, which synchronizes events, tasks and contacts between Outlook and Google, SOGo, Horde or any other CalDAV or CardDAV server. Supported Outlook versions are 2016, 2013, 2010 and 2007.


  • free and open-source software (FOSS), the only free Outlook CalDav plugin (AGPL license)
  • tested CalDAV servers: SOGo, Google Calendar, Horde Kronolith, NextCloud, OwnCloud, SabreDAV, Synology NAS, GroupOffice, , Yandex, OpenX-change, Posteo, Landmarks, Kolab, Zoho Calendar, GMX, Tine 2.0, Fruux, Mac OS X Server, iCloud,, Radicale, Cozy Cloud, Cyrus Imap 2.5
  • two-way-sync
  • modern WPF GUI
  • Supporting OAuth2 for Google
  • SSL/TLS support, support for self-signed certificates
  • Manual proxy configuration support for NTLM or basic auth proxies
  • Autodiscovery of calendars and adressbooks via well-known redirects or DNS SRV/TXT lookups
  • configurable sync range
  • sync multiple calendars per profile
  • sync reminders, categories, recurrences with exceptions, importance, transparency
  • sync organizer and attendees and own response status
  • task support
  • CardDAV support to sync contacts (distribution lists planned)
  • Google native Contacts API support with mapping of Google contact groups to Outlook categories.
  • Google Tasklists support (sync via Google Task Api with Outlook task folders)
  • sync contact pictures, categories, notes and x509 certificates
  • manual or time-triggered sync
  • change-triggered sync
  • sync triggered by Outlook Send/Receive
  • Category Filtering (sync CalDAV calendar to Outlook categories)
  • map CalDAV server colors to Outlook category colors
  • show reports of last sync runs and status
  • configurable system Tray Icon with notifications
  • bulk creation of multiple profiles
  • Use server settings from Outlook IMAP/POP3 account profile
  • Map Windows to standard IANA/Olson timezones
  • Configurable mapping of Outlook custom properties

The project page is here:

IPP and Airprint shared printer on CentOS Linux

yum install cups -y
yum install foomatic* -y
yum install avahi avahi-tools -y

systemctl enable cups
 systemctl enable avahi-daemon
 systemctl start cups
 systemctl start avahi-daemon

after each change in configuration, restart both of them using

systemctl restart cups
 systemctl restart avahi-daemon

lynx localhost:631  – allow from remote, then from your computer go to prinserver:631 and configure cups via web gui.

If you can’t see the printer from IOS or OSX, check /etc/avahi/services if a proper .service file was created,

if not, use the python generator from here:

In order to use bonjour/airprint from Windows machines, install first

Handbrake Recipe

Again, a personal recipe, no questions asked

profile ipad + CBR 2000 double pas
anamorphic none
1280×720 @2000

Join files:

Create a list.txt with the following content:
file ‘c:\TEST\1.mp4’
file ‘c:\TEST\2.mp4’
file ‘c:\TEST\3.mp4’
Run in CLI:
ffmpeg -f concat -i list.txt -codec copy out.mkv

mov > mp4 vlc not play in wmp

CentOS 7 root password reset

If we have a CentOS 7 or Red Hat Enterprise Linux (RHEL 7) with a selinux in enforced mode, the password resetting procedure need to be modified.

  • From the Grub menu type “e” in order to edit the default menu item.
  • Find the line that starts with “linux16”. At the end of this line append the text “rd.break”
  • touch /.autorelabel
  • Type exit once
  • type reboot