diff --git a/src/main/scala/scoverage/IOUtils.scala b/src/main/scala/scoverage/IOUtils.scala
index 0b41ad6d..2e681c51 100644
--- a/src/main/scala/scoverage/IOUtils.scala
+++ b/src/main/scala/scoverage/IOUtils.scala
@@ -2,6 +2,9 @@ package scoverage
 
 import java.io._
 import scala.xml.{XML, Utility, Node}
+import scala.collection.Set
+import scala.collection.mutable
+import scala.io.Source
 
 /** @author Stephen Samuel */
 object IOUtils {
@@ -28,14 +31,18 @@ object IOUtils {
   })
 
   // loads all the invoked statement ids from the given files
-  def invoked(files: Seq[File]): Seq[Int] = {
-    files.flatMap {
-      file =>
-      val reader = new BufferedReader(new FileReader(file))
-      val line = reader.readLine()
+  def invoked(files: Seq[File]): Set[Int] = {
+    val acc = mutable.Set[Int]()
+    files.foreach { file =>
+      val reader = Source.fromFile(file)
+      for (line <- reader.getLines()) {
+        if (!line.isEmpty) {
+          acc += line.toInt
+        }
+      }
       reader.close()
-      line.split(";").filterNot(_.isEmpty).map(_.toInt)
     }
+    acc
   }
 
   /**
diff --git a/src/main/scala/scoverage/Invoker.scala b/src/main/scala/scoverage/Invoker.scala
index cf870691..cee55f80 100644
--- a/src/main/scala/scoverage/Invoker.scala
+++ b/src/main/scala/scoverage/Invoker.scala
@@ -31,6 +31,6 @@ object Invoker {
       writer = new FileWriter(file, true)
       threadFile.set(writer)
     }
-    writer.append(id.toString + ';').flush()
+    writer.append(id.toString + '\n').flush()
   }
 }
diff --git a/src/test/scala/scoverage/IOUtilsTest.scala b/src/test/scala/scoverage/IOUtilsTest.scala
index 043a7e48..fa0ed097 100644
--- a/src/test/scala/scoverage/IOUtilsTest.scala
+++ b/src/test/scala/scoverage/IOUtilsTest.scala
@@ -46,7 +46,7 @@ class IOUtilsTest extends FunSuite with MockitoSugar with OneInstancePerTest {
   test("io utils should parse measurement file") {
     val file = File.createTempFile("scoveragemeasurementtest", "txt")
     val writer = new FileWriter(file)
-    writer.write("1;5;9;;10;")
+    writer.write("1\n5\n9\n\n10\n")
     writer.close()
     val invoked = IOUtils.invoked(Seq(file))
     assert(invoked.toSet === Set(1, 5, 9, 10))
@@ -62,12 +62,12 @@ class IOUtilsTest extends FunSuite with MockitoSugar with OneInstancePerTest {
 
     val file1 = File.createTempFile("scoverage.measurements.1", "txt")
     val writer1 = new FileWriter(file1)
-    writer1.write("1;5;9;;10;")
+    writer1.write("1\n5\n9\n\n10\n")
     writer1.close()
 
     val file2 = File.createTempFile("scoverage.measurements.2", "txt")
     val writer2 = new FileWriter(file2)
-    writer2.write("1;7;14;;2;")
+    writer2.write("1\n7\n14\n\n2\n")
     writer2.close()
 
     val files = IOUtils.findMeasurementFiles(file1.getParent)