diff --git a/build.sbt b/build.sbt
index 63a5eeeb..853ce936 100644
--- a/build.sbt
+++ b/build.sbt
@@ -106,6 +106,7 @@ val io = (project in file("io"))
         ) map (version => organization.value %% moduleName.value % version)
     }),
     mimaBinaryIssueFilters ++= Seq(
+      exclude[FinalClassProblem]("sbt.internal.io.MacJNA$TimeBuf"),
       // MiMa doesn't treat effectively final members as final
       // WORKAROUND typesafehub/migration-manager#162
       exclude[FinalMethodProblem]("sbt.io.SimpleFilter.accept"),
diff --git a/io/src/main/java/sbt/internal/io/MacJNA.java b/io/src/main/java/sbt/internal/io/MacJNA.java
index bc30dcb9..7ad182b2 100644
--- a/io/src/main/java/sbt/internal/io/MacJNA.java
+++ b/io/src/main/java/sbt/internal/io/MacJNA.java
@@ -45,7 +45,7 @@ public List<String> getFieldOrder() {
     };
   }
 
-  public static class TimeBuf extends Structure {
+  public static final class TimeBuf extends Structure {
     public int size;
     public long tv_sec;
     public long tv_nsec;