Error while adding liquidCrystal I2C.h and other library errors

Seems that the library server is having a bad Sunday.

it started out only faulting randomly while uploading a known good sketch. First it was DHT.h that was faulting then I switched to this known good test sketch.
I can not add the librarys to my library folder anymore by clicking on the STAR. The error received when clicking on the STAR is "Error while adding liquidCrystal I2C.h" or any library for that matter.

./opt/arduino-builder/arduino-builder -compile -core-api-version 10611 -hardware opt/arduino-builder/hardware -hardware ./opt/cores -tools opt/arduino-builder/tools -tools ./opt/tools -built-in-libraries opt/libraries/latest -logger humantags -fqbn arduino:avr:uno -build-cache /tmp -build-path /tmp/147997508/build -verbose -prefs runtime.tools.avr-gcc.path=./opt/tools/avr-gcc/5.4.0-atmel3.6.1-arduino2 -prefs runtime.tools.avrdude.path=./opt/tools/avrdude/6.3.0-arduino14 -prefs runtime.tools.arduinoOTA.path=./opt/tools/arduinoOTA/1.2.1 -libraries /tmp/147997508/custom -libraries /tmp/147997508/pinned /tmp/147997508/HelloWorld_copy

Using library Wire at version 1.0 in folder: /home/ubuntu/opt/cores/arduino/avr/libraries/Wire

/tmp/147997508/HelloWorld_copy/HelloWorld_copy.ino:5:31: fatal error: LiquidCrystal_I2C.h: No such file or directory

compilation terminated.

exit status 1

Is this a library you have personally added or one that was available in the editor ?
Which board are you using ?