user19838: I've never much issue importing a library to my master sketchbook location, restarting Arduino, then using the library examples. Today is a different story:

I'm loading RCLib which is part of this ArduinoLibraries family
RCLib requires PinChangeInt

So everything is in my sketchbook location right? Arduino > Preferences > Sketchbook Location
Still I'm getting compiler errors about missing libraries:
/Users/Jackson/Documents/Arduino/ArduinoLibraries-master/RCLib/Examples/Maga6ChanelsA8_A13/Maga6ChanelsA8_A13.ino:7:86: fatal error: PinChangeInt.h: No such file or directory
 #include "PinChangeInt.h"

I've even tried #include <PinChangeInt.h> Which makes more sense since this is a system library.
What is going on here?
The sketch I'm trying to run:
/**This is an example of using the RCLib with a mega and pinchangeint
 * This example isprovided as is by Jantje
 * Congratualtions, constructive feedback and I like it can be send to eclipse@baeyens.it
 **/

#define NUM_RC_CHANNELS 6 //You need to specify how many pins you want to use
#include "PinChangeInt.h"  //If you need pinchangeint you need to include this header
const uint8_t RC_Channel_Pin[NUM_RC_CHANNELS]={
  A8,A9,A10,A11,A12,A13};//Here I specify I want to listen to pins A8 to A13 of my mega

uint16_t RC_Channel_Value[NUM_RC_CHANNELS]; //This variable will contain the values read from the RC signal
#include "RCLib.h" //This include needs all declarations above. Do not try to move it up or it won't compile

Arduino v1.6.9 | OSX 10.11.4

user19838: I had downloaded PinChangeInterrupt through Arduino
Sketch > Include Library > Manage Libraries... > Filter your search... > PinChangeInterrupt > Install
I thought this is all I needed but I was wrong. This differs from the popular PinChangeInt library. Ultimately the file names where slightly different which is why my file was showing as missing. I found this out by manually looking at the file names in the library I was trying to used and comparing them against my includes.

19838: <p>I've never much issue importing a library to my master sketchbook location, restarting Arduino, then using the library examples. Today is a different story:</p>

<ol>
<li>I'm loading <a href="https://github.com/jantje/ArduinoLibraries/tree/master/RCLib" rel="nofollow">RCLib</a> which is part of this <a href="https://github.com/jantje/ArduinoLibraries" rel="nofollow">ArduinoLibraries</a> family</li>
<li>RCLib requires <a href="https://github.com/GreyGnome/PinChangeInt" rel="nofollow">PinChangeInt</a></li>
</ol>

<p>So everything is in my sketchbook location right? <code>Arduino &gt; Preferences &gt; Sketchbook Location</code></p>

<p>Still I'm getting compiler errors about missing libraries:</p>

<pre><code>/Users/Jackson/Documents/Arduino/ArduinoLibraries-master/RCLib/Examples/Maga6ChanelsA8_A13/Maga6ChanelsA8_A13.ino:7:86: fatal error: PinChangeInt.h: No such file or directory
 #include "PinChangeInt.h"
</code></pre>

<p>I've even tried <code>#include &lt;PinChangeInt.h&gt;</code> Which makes more sense since this is a system library.</p>

<p><strong>What is going on here?</strong></p>

<p>The sketch I'm trying to run:</p>

<pre><code>/**This is an example of using the RCLib with a mega and pinchangeint
 * This example isprovided as is by Jantje
 * Congratualtions, constructive feedback and I like it can be send to eclipse@baeyens.it
 **/

#define NUM_RC_CHANNELS 6 //You need to specify how many pins you want to use
#include "PinChangeInt.h"  //If you need pinchangeint you need to include this header
const uint8_t RC_Channel_Pin[NUM_RC_CHANNELS]={
  A8,A9,A10,A11,A12,A13};//Here I specify I want to listen to pins A8 to A13 of my mega

uint16_t RC_Channel_Value[NUM_RC_CHANNELS]; //This variable will contain the values read from the RC signal
#include "RCLib.h" //This include needs all declarations above. Do not try to move it up or it won't compile
</code></pre>

<p><em>Arduino v1.6.9 | OSX 10.11.4</em></p>
 19838: <p>I had downloaded PinChangeInterrupt through Arduino</p>

<p>Sketch > Include Library > Manage Libraries... > <em>Filter your search...</em> > PinChangeInterrupt > Install</p>

<p>I thought this is all I needed but I was wrong. This differs from the popular <a href="https://github.com/GreyGnome/PinChangeInt" rel="nofollow">PinChangeInt library</a>. Ultimately the file names where slightly different which is why my file was showing as missing. I found this out by manually looking at the file names in the library I was trying to used and comparing them against my includes.</p>
