diff --git a/web/source/kmwdevice.ts b/web/source/kmwdevice.ts
index 209587c65e..fce6196117 100644
--- a/web/source/kmwdevice.ts
+++ b/web/source/kmwdevice.ts
@@ -77,7 +77,10 @@ namespace com.keyman {
           // Starting with 13.1, "Macintosh" can reflect iPads (by default) or iPhones 
           // (by user setting); a new "Request Desktop Website" setting for Safari will
           // change the user agent string to match a desktop Mac.
-          let regex = /Intel Mac OS X (10(?:_\d+)+)/i;
+          //
+          // Firefox uses '.' between version components, while Chrome and Safari use
+          // '_' instead.  So, we have to check for both.  Yay.
+          let regex = /Intel Mac OS X (10(?:[_\.]\d+)+)/i;
           let results = regex.exec(agent);
           
           // Match result:  a version string with components separated by underscores.
diff --git a/web/unit_tests/CI.conf.js b/web/unit_tests/CI.conf.js
index a5e5fb803b..386142fd0e 100644
--- a/web/unit_tests/CI.conf.js
+++ b/web/unit_tests/CI.conf.js
@@ -43,14 +43,12 @@ module.exports = function(config) {
    * Definition of browser sets possibly relevant for testing.
    */
   var CURRENT_MAC_LAUNCHERS = {
-    // Disabled due to a long period BrowserStack failing to actually run the tests on
-    // the browser/platform combo.
-    // bs_firefox_mac: {
-    //   browser: 'firefox',
-    //   browser_version: '62',
-    //   os: 'OS X',
-    //   os_version: 'Mojave'
-    // },
+    bs_firefox_mac: {
+      browser: 'firefox',
+      browser_version: '62',
+      os: 'OS X',
+      os_version: 'Mojave'
+    },
     bs_safari_mac_m: {
       browser: 'safari',
       browser_version: '13',
@@ -162,7 +160,7 @@ module.exports = function(config) {
 
     // level of logging
     // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
-    logLevel: config.LOG_INFO,
+    logLevel: config.LOG_DEBUG,
 
     // Concurrency level
     // For CI, it really helps to keep a nice, clean set of output logs.
diff --git a/web/unit_tests/base.conf.js b/web/unit_tests/base.conf.js
index 17070b9f68..408d5064fb 100644
--- a/web/unit_tests/base.conf.js
+++ b/web/unit_tests/base.conf.js
@@ -7,6 +7,9 @@ module.exports = {
   // base path that will be used to resolve all patterns (eg. files, exclude)
   basePath: '..',
 
+  // Safeguards against disconnecting after starting tests.
+  browserNoActivityTimeout: 60000,
+
   client: {
     /* `client.args` here is passed to the test runner page as `__karma__.config.args`.  
      *
@@ -37,6 +40,7 @@ module.exports = {
     'unit_tests/recorder_InputEvents.js', // The object definitions used to generate/replicate key events for engine tests.
                                           // Includes KMW's Device class, which is used by test_utils below.
     'unit_tests/dev_resources.js',  // Defines com.keyman.dom objects separate from KMW for unit testing.
+    'unit_tests/test_init_check.js', // Ensures that tests will initialize properly
     'unit_tests/test_utils.js', // A basic utility script useful for constructing tests
     'unit_tests/cases/**/*.js', // Where the tests actually reside.
     'unit_tests/json/**/*.json', // Where pre-loaded JSON resides.
diff --git a/web/unit_tests/cases/attachmentAPI.js b/web/unit_tests/cases/attachmentAPI.js
index a61b40e690..087cdf9265 100644
--- a/web/unit_tests/cases/attachmentAPI.js
+++ b/web/unit_tests/cases/attachmentAPI.js
@@ -4,6 +4,7 @@ describe('Attachment API', function() {
   this.timeout(kmwconfig.timeouts.standard);
 
   before(function(done) {
+    assert.isFalse(com.keyman.karma.DEVICE_DETECT_FAILURE, "Cannot run due to device detection failure.");
     fixture.setBase('unit_tests/fixtures');
 
     this.timeout(kmwconfig.timeouts.scriptLoad * 3);
diff --git a/web/unit_tests/cases/basics.js b/web/unit_tests/cases/basics.js
index 7987a68351..269f2c9b20 100644
--- a/web/unit_tests/cases/basics.js
+++ b/web/unit_tests/cases/basics.js
@@ -3,6 +3,11 @@ var assert = chai.assert;
 describe('Basic KeymanWeb', function() {
   this.timeout(kmwconfig.timeouts.standard);
 
+  before(function() {
+    // These tests require use of KMW's device-detection functionality.
+    assert.isFalse(com.keyman.karma.DEVICE_DETECT_FAILURE, "Cannot run due to device detection failure.");
+  })
+
   beforeEach(function(done) {
     this.timeout(kmwconfig.timeouts.scriptLoad);
 
diff --git a/web/unit_tests/cases/element_interfaces.js b/web/unit_tests/cases/element_interfaces.js
index e1ed36b69c..3a2321126e 100644
--- a/web/unit_tests/cases/element_interfaces.js
+++ b/web/unit_tests/cases/element_interfaces.js
@@ -1177,6 +1177,11 @@ describe('Element Input/Output Interfacing', function() {
    * TODO:  Design and implement some 'complex', cross-Node selection tests.
    */
   describe('Wrapper: Content-Editable Elements (using DIVs)', function() {
+    before(function() {
+      // These tests require use of KMW's device-detection functionality.
+      assert.isFalse(com.keyman.karma.DEVICE_DETECT_FAILURE, "Cannot run due to device detection failure.");
+    })
+
     describe('Caret Handling', function() {
       describe('hasSelection', function() {
         it('correctly recognizes Selection ownership', function () {
@@ -1264,6 +1269,11 @@ describe('Element Input/Output Interfacing', function() {
     // We'll need a larger timeout.
     this.timeout(kmwconfig.timeouts.scriptLoad);
 
+    before(function() {
+      // These tests require use of KMW's device-detection functionality.
+      assert.isFalse(com.keyman.karma.DEVICE_DETECT_FAILURE, "Cannot run due to device detection failure.");
+    })
+
     beforeEach(function(done) {
       // Per-test creation of reg. pair and dummy elements, since IFrames are async.
       // Relies on the main-level's renewal of the overall fixture to be processed first.
diff --git a/web/unit_tests/cases/touch_aliases.js b/web/unit_tests/cases/touch_aliases.js
index 1af6139f32..a559a21394 100644
--- a/web/unit_tests/cases/touch_aliases.js
+++ b/web/unit_tests/cases/touch_aliases.js
@@ -93,6 +93,11 @@ describe('TouchAliasElement', function() {
   });
 
   describe("With ['base']", function() {
+    before(function() {
+      // These tests require use of KMW's device-detection functionality.
+      assert.isFalse(com.keyman.karma.DEVICE_DETECT_FAILURE, "Cannot run due to device detection failure.");
+    })
+    
     it('correctly aliases upon construction', function(done) {
       var input = document.getElementById(DynamicElements.addInput());
       input.value = "apples";
diff --git a/web/unit_tests/test.sh b/web/unit_tests/test.sh
index 3a6ab9a1c5..133dccf8b6 100755
--- a/web/unit_tests/test.sh
+++ b/web/unit_tests/test.sh
@@ -4,7 +4,7 @@
 # It's rigged to be callable by NPM to facilitate testing during development when in other folders.
 
 display_usage ( ) {
-    echo "test.sh [-CI | -debug | -? | -h | -help] [-reporter <reporter>]"
+    echo "test.sh [-CI | -debug | -? | -h | -help] | [-log-level <level>] | [-reporter <reporter>]"
     echo
     echo "  -CI               to run unit tests in CI mode on BrowserStack."
     echo "                    This script requires your credentials to be set in environment variables - see "
@@ -13,6 +13,9 @@ display_usage ( ) {
     echo "  -debug            to establish a Karma server that facilitates unit test debugging"
     echo "                    Not compatible with -CI."
     echo ""
+    echo "  -log-level        to set the logging level used by Karma."
+    echo "                    Valid options: 'debug', 'info', 'warn', 'error', 'disable'"
+    echo ""
     echo "  -reporter         sets the test engine to utilize the specified <reporter>."
     echo "                    Valid options:  BrowserStack, teamcity, dots, progress, mocha"
     echo ""
@@ -65,6 +68,10 @@ while [[ $# -gt 0 ]] ; do
         -CI)
             CONFIG=CI.conf.js
             ;;
+        -log-level)
+            shift
+            FLAGS="--log-level=$1 $FLAGS"
+            ;;
         -debug)
             # Disables the default 'run once, then done' configuration needed for CI.
             DEBUG=true
@@ -103,7 +110,7 @@ cd $BASE_PATH/../source
 ./build_dev_resources.sh
 
 npm --no-color run modernizr -- -c unit_tests/modernizr.config.json -d unit_tests/modernizr.js
-npm --no-color run karma -- start --log-level=debug $FLAGS $BROWSERS unit_tests/$CONFIG
+npm --no-color run karma -- start $FLAGS $BROWSERS unit_tests/$CONFIG
 
 CODE=$?
 
diff --git a/web/unit_tests/test_init_check.js b/web/unit_tests/test_init_check.js
new file mode 100644
index 0000000000..6b1619a950
--- /dev/null
+++ b/web/unit_tests/test_init_check.js
@@ -0,0 +1,28 @@
+// A simple "does device detection work properly" unit test.
+// We'll let things break after this reports, since this will likely signal a LOT of other failures.
+var assert = chai.assert;
+
+/* Note - we still have to prevent errors setting up test resources;
+ * Karma will fail to report errors for affected browsers otherwise.
+ *
+ * This simply gives us a test report with the error that can be shown
+ * if we disable other tests when this fails.
+ */
+describe('Test Initialization', function() {
+  // We can't use kmwconfig timeouts yet (they rely on test success), so we simply give
+  // this should-be-simple test a nice, large block of time to run.
+  this.timeout(15000);
+
+  it("Detects device without JS errors", function() {
+    var device;
+    try {
+      device = new com.keyman.Device();
+      device.detect();
+
+      console.log("Detected platform: " + device.browser + " on " + device.OS + " with form factor " + device.formFactor);
+    } catch (err) {
+      console.error("Error during device detection: " + err.toString());
+      assert.fail(err);
+    }
+  });
+});
\ No newline at end of file
diff --git a/web/unit_tests/test_utils.js b/web/unit_tests/test_utils.js
index bdb50d0267..6830727aea 100644
--- a/web/unit_tests/test_utils.js
+++ b/web/unit_tests/test_utils.js
@@ -1,9 +1,23 @@
 // KeymanWeb test suite - processing of the Karma configuration's client.args parameter.
 
+com = com || {};
+com.keyman = com.keyman || {};
+com.keyman.karma = com.keyman.karma || {};
+com.keyman.karma.DEVICE_DETECT_FAILURE = false;
+
 (function() {
-  var device = new com.keyman.Device();
-  device.detect();
-  var mobile = (device.formFactor != 'desktop');
+  // Default value in case of device-detection failure.
+  var mobile = false;
+
+  try {
+    var device = new com.keyman.Device();
+    device.detect();
+
+    mobile = (device.formFactor != 'desktop');
+  } catch (err) {
+    // Sets a warning flag that unit-test files can use to disable themselves.
+    com.keyman.karma.DEVICE_DETECT_FAILURE = true;
+  }
 
   var kmwconfig = window['kmwconfig'] = {mobile: mobile};