diff --git a/meteor b/meteor
index 6e5eb77379..2b1f35547f 100755
--- a/meteor
+++ b/meteor
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-BUNDLE_VERSION=0.3.74
+BUNDLE_VERSION=0.3.78
 
 # OS Check. Put here because here is where we download the precompiled
 # bundles that are arch specific.
diff --git a/scripts/generate-dev-bundle.sh b/scripts/generate-dev-bundle.sh
index f67f143106..d2ad0ff957 100755
--- a/scripts/generate-dev-bundle.sh
+++ b/scripts/generate-dev-bundle.sh
@@ -121,7 +121,11 @@ cd "${DIR}/lib"
 
 # TODO Move this into dev-bundle-tool-package.js when it can be safely
 # installed that way (i.e. without build nan/runas build errors).
-npm install pathwatcher@2.3.5
+# XXX This contains a patch to expose the errno from failed syscalls, so
+# we can better understand why some users can't use pathwatcher.
+# We have to install from the npm registry in order to get coffeescript
+# output.  The patch is https://github.com/atom/node-pathwatcher/pull/53
+npm install meteor-pathwatcher-tweaks@2.3.5
 
 # Clean up some bulky stuff.
 cd node_modules
diff --git a/tools/safe-pathwatcher.js b/tools/safe-pathwatcher.js
index 6469e0a2e8..20402447c6 100644
--- a/tools/safe-pathwatcher.js
+++ b/tools/safe-pathwatcher.js
@@ -2,12 +2,16 @@ var fs = require("fs");
 
 // Set this env variable to a truthy value to force fs.watchFile instead
 // of pathwatcher.watch.
-var canUsePathwatcher = !process.env.METEOR_WATCH_FORCE_POLLING;
+var PATHWATCHER_ENABLED = !process.env.METEOR_WATCH_FORCE_POLLING;
 
-var pollingInterval = canUsePathwatcher
-  // Set this env variable to alter the watchFile polling interval.
-  ? ~~process.env.METEOR_WATCH_POLLING_INTERVAL_MS || 5000
-  : 500;
+var DEFAULT_POLLING_INTERVAL =
+      ~~process.env.METEOR_WATCH_POLLING_INTERVAL_MS || 5000;
+
+
+var NO_PATHWATCHER_POLLING_INTERVAL =
+      ~~process.env.METEOR_WATCH_POLLING_INTERVAL_MS || 500;
+
+var suggestedRaisingWatchLimit = false;
 
 exports.watch = function watch(absPath, callback) {
   var lastPathwatcherEventTime = 0;
@@ -23,8 +27,48 @@ exports.watch = function watch(absPath, callback) {
     callback.apply(this, arguments);
   }
 
-  var watcher = canUsePathwatcher &&
-    require("pathwatcher").watch(absPath, pathwatcherWrapper);
+  var watcher = null;
+  if (PATHWATCHER_ENABLED) {
+    var pathwatcher = require('meteor-pathwatcher-tweaks');
+    try {
+      watcher = pathwatcher.watch(absPath, pathwatcherWrapper);
+    } catch (e) {
+      // If it isn't an actual pathwatcher failure, rethrow.
+      if (e.message !== 'Unable to watch path')
+        throw e;
+      var constants = require('constants');
+      var archinfo = require('./archinfo.js');
+      if (! suggestedRaisingWatchLimit &&
+          // Note: the not-super-documented require('constants') maps from
+          // strings to SYSTEM errno values. System errno values aren't the same
+          // as the numbers used internally by libuv! It would be nice to just
+          // make pathwatcher process the system errno into a string for us, but
+          // this is a pain, because posix doesn't give us a function to give us
+          // 'ENOSPC'-style strings (just the longer strings that strerror gives
+          // you). While libuv does give us uv_err_name, it takes in a *UV*
+          // errno value, which is different from the system errno value, and
+          // the translation function is not exposed:
+          // https://github.com/libuv/libuv/issues/79
+          e.code === constants.ENOSPC &&
+          // The only suggestion we currently have is for Linux.
+          archinfo.matches(archinfo.host(), 'os.linux')) {
+        suggestedRaisingWatchLimit = true;
+        var Console = require('./console.js').Console;
+        // XXX If we're comfortable with this message appearing in the new user
+        // experience, change it from debug to arrowWarn.
+        Console.debug(
+          "It looks like a simple tweak to your system's configuration will " +
+            "make many tools (including this meteor command) more efficient. " +
+            "To learn more, see " +
+            Console.url("https://github.com/meteor/meteor/wiki/File-Change-Watcher-Efficiency"));
+      }
+      // ... ignore the error.  We'll still have watchFile, which is good
+      // enough.
+    }
+  }
+
+  var pollingInterval = watcher
+        ? DEFAULT_POLLING_INTERVAL : NO_PATHWATCHER_POLLING_INTERVAL;
 
   function watchFileWrapper() {
     // If a pathwatcher event fired in the last polling interval, ignore
@@ -34,10 +78,10 @@ exports.watch = function watch(absPath, callback) {
     }
   }
 
-  // We use fs.watchFile in addition to pathwatcher.watch as a fail-safe
-  // to detect file changes even on network file systems.  However (unless
-  // canUsePathwatcher is false), we use a relatively long default polling
-  // interval of 5000ms to save CPU cycles.
+  // We use fs.watchFile in addition to pathwatcher.watch as a fail-safe to
+  // detect file changes even on network file systems.  However (unless the user
+  // disabled pathwatcher or this pathwatcher call failed), we use a relatively
+  // long default polling interval of 5000ms to save CPU cycles.
   fs.watchFile(absPath, {
     persistent: false,
     interval: pollingInterval
diff --git a/tools/watch.js b/tools/watch.js
index 7293d6cd4e..4062507236 100644
--- a/tools/watch.js
+++ b/tools/watch.js
@@ -463,6 +463,8 @@ _.extend(Watcher.prototype, {
       if (stat === null || stat.isFile()) {
         if (_.has(self.watchSet.files, absPath)) {
           self._fireIfFileChanged(absPath);
+          // XXX #3335 We probably should check again in a second, due to low
+          // filesystem modtime resolution.
         }
 
       } else if (stat.isDirectory()) {
@@ -500,6 +502,8 @@ _.extend(Watcher.prototype, {
           return self.stopped ||
             (absPath === info.absPath &&
              self._fireIfDirectoryChanged(info, true));
+          // XXX #3335 We probably should check again in a second, due to low
+          // filesystem modtime resolution.
         });
       }
     });