diff --git a/io/src/main/scala/sbt/internal/io/Milli.scala b/io/src/main/scala/sbt/internal/io/Milli.scala
index e5962dd8..4d8f1dc4 100644
--- a/io/src/main/scala/sbt/internal/io/Milli.scala
+++ b/io/src/main/scala/sbt/internal/io/Milli.scala
@@ -79,6 +79,7 @@ private abstract class MilliNative[Native] extends Milli {
  * FFI for standard C library.
  */
 private sealed trait PosixBase extends Library {
+
   /** http://www.cplusplus.com/reference/cstring/strerror/ */
   def strerror(errnum: Int): String
 }
@@ -368,7 +369,7 @@ object Milli {
     }
   }
 
-  private val milli =
+  val milli: Milli =
     if (jdkTimestamps || !isIntel)
       JavaMilli
     else
diff --git a/io/src/main/scala/sbt/internal/io/Retry.scala b/io/src/main/scala/sbt/internal/io/Retry.scala
index 636f6998..94ece31f 100644
--- a/io/src/main/scala/sbt/internal/io/Retry.scala
+++ b/io/src/main/scala/sbt/internal/io/Retry.scala
@@ -11,7 +11,6 @@
 package sbt.internal.io
 import java.io.IOException
 
-import scala.annotation.tailrec
 import scala.util.control.NonFatal
 
 private[sbt] object Retry {
@@ -20,35 +19,29 @@ private[sbt] object Retry {
     try System.getProperty("sbt.io.retry.limit", defaultLimit.toString).toInt
     catch { case NonFatal(_) => defaultLimit }
   }
-  private[sbt] def apply[T](f: => T, excludedExceptions: Class[_ <: IOException]*): T =
+  private[sbt] def apply[@specialized T](f: => T, excludedExceptions: Class[_ <: IOException]*): T =
     apply(f, limit, excludedExceptions: _*)
-  private[sbt] def apply[T](
+  private[sbt] def apply[@specialized T](
       f: => T,
       limit: Int,
       excludedExceptions: Class[_ <: IOException]*
   ): T = {
-    lazy val filter: Exception => Boolean = excludedExceptions match {
+    def filter(e: Exception): Boolean = excludedExceptions match {
       case s if s.nonEmpty =>
-        (e: Exception) => !excludedExceptions.exists(_.isAssignableFrom(e.getClass))
+        !excludedExceptions.exists(_.isAssignableFrom(e.getClass))
       case _ =>
-        (_: Exception) => true
+        true
     }
-    @tailrec
-    def impl(attempt: Int): T = {
-      val (retry, res) = try false -> Right(f)
-      catch {
-        case e: IOException if filter(e) && (attempt < limit) => (true, Left(e))
-        case e: IOException                                   => (false, Left(e))
-      }
-      if (retry) {
-        Thread.sleep(0); impl(attempt + 1)
-      } else {
-        res match {
-          case Right(r) => r
-          case Left(e)  => throw e
-        }
+    var attempt = 1
+    while (attempt < limit) {
+      try {
+        return f
+      } catch {
+        case e: IOException if filter(e) && (attempt < limit) =>
+          Thread.sleep(0);
+          attempt += 1
       }
     }
-    impl(1)
+    throw new IllegalStateException()
   }
 }
diff --git a/io/src/main/scala/sbt/internal/nio/SwovalConverters.scala b/io/src/main/scala/sbt/internal/nio/SwovalConverters.scala
index b1d40f8c..81d080be 100644
--- a/io/src/main/scala/sbt/internal/nio/SwovalConverters.scala
+++ b/io/src/main/scala/sbt/internal/nio/SwovalConverters.scala
@@ -54,7 +54,9 @@ private[sbt] object SwovalFileTreeView extends FileTreeView.Nio[FileAttributes]
         }
         result.result()
       },
-      classOf[NotDirectoryException],
-      classOf[NoSuchFileException]
+      excludedExceptions: _*
     )
+
+  private val excludedExceptions =
+    List(classOf[NotDirectoryException], classOf[NoSuchFileException])
 }
diff --git a/io/src/main/scala/sbt/io/IO.scala b/io/src/main/scala/sbt/io/IO.scala
index 3d95d299..78bb2948 100644
--- a/io/src/main/scala/sbt/io/IO.scala
+++ b/io/src/main/scala/sbt/io/IO.scala
@@ -27,6 +27,7 @@ import sbt.nio.file.FileTreeView
 import scala.Function.tupled
 import scala.annotation.tailrec
 import scala.collection.JavaConverters._
+import scala.collection.immutable
 import scala.collection.immutable.TreeSet
 import scala.collection.mutable.{ HashMap, HashSet }
 import scala.reflect.{ Manifest => SManifest }
@@ -1404,7 +1405,7 @@ object IO {
    */
   def getModifiedTimeOrZero(file: File): Long =
     try {
-      Retry(Milli.getModifiedTime(file), classOf[FileNotFoundException])
+      Retry(Milli.getModifiedTime(file), excludeFileNotFound: _*)
     } catch {
       case _: FileNotFoundException =>
         val unnormalized = file.toPath
@@ -1429,7 +1430,7 @@ object IO {
    */
   def setModifiedTimeOrFalse(file: File, mtime: Long): Boolean =
     try {
-      Retry(Milli.setModifiedTime(file, mtime), classOf[FileNotFoundException])
+      Retry(Milli.setModifiedTime(file, mtime), excludeFileNotFound: _*)
       true
     } catch {
       case _: FileNotFoundException =>
@@ -1461,4 +1462,8 @@ object IO {
     // see Java bug #6791812
     setModifiedTimeOrFalse(targetFile, math.max(last, 0L))
   }
+
+  private val excludeFileNotFound: immutable.Seq[Class[_ <: IOException]] = List(
+    classOf[FileNotFoundException]
+  )
 }
diff --git a/io/src/main/scala/sbt/nio/file/FileTreeView.scala b/io/src/main/scala/sbt/nio/file/FileTreeView.scala
index e9e5a670..9029d9e8 100644
--- a/io/src/main/scala/sbt/nio/file/FileTreeView.scala
+++ b/io/src/main/scala/sbt/nio/file/FileTreeView.scala
@@ -53,16 +53,18 @@ object FileTreeView {
    * An implementation of [[FileTreeView]] that uses built in jvm apis. This implementation
    * will throw an IOException if the input path is not a directory or doesn't exist.
    */
-  val nio: FileTreeView.Nio[FileAttributes] = (path: Path) =>
-    Retry(
-      {
-        val stream = Files.list(path)
-        try stream.iterator.asScala.flatMap(p => FileAttributes(p).toOption.map(p -> _)).toVector
-        finally stream.close()
-      },
-      classOf[NotDirectoryException],
-      classOf[NoSuchFileException]
-    )
+  val nio: FileTreeView.Nio[FileAttributes] = {
+    val excludedExceptions = List(classOf[NotDirectoryException], classOf[NoSuchFileException])
+    (path: Path) =>
+      Retry(
+        {
+          val stream = Files.list(path)
+          try stream.iterator.asScala.flatMap(p => FileAttributes(p).toOption.map(p -> _)).toVector
+          finally stream.close()
+        },
+        excludedExceptions: _*
+      )
+  }
 
   /**
    * Adds additional methods to [[FileTreeView]]. This api may be changed so it should not be