diff --git a/src/main/java/com/google/devtools/build/lib/actions/ActionExecutionContext.java b/src/main/java/com/google/devtools/build/lib/actions/ActionExecutionContext.java
index 7f04336..986b741 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/ActionExecutionContext.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/ActionExecutionContext.java
@@ -185,6 +185,11 @@
         : executor.getExecRoot();
   }
 
+  @Nullable
+  public FileSystem getActionFileSystem() {
+    return actionFileSystem;
+  }
+
   /**
    * Returns the path for an ActionInput.
    *
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeActionExecutor.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeActionExecutor.java
index 9a370f6..f5ff6e2 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeActionExecutor.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeActionExecutor.java
@@ -782,8 +782,27 @@
     }
     actionExecutionContext.getEventHandler().post(new ScanningActionEvent(action));
     try {
-      return action.discoverInputs(actionExecutionContext);
+      Iterable<Artifact> artifacts = action.discoverInputs(actionExecutionContext);
+
+      // Input discovery may have been affected by lost inputs. If an action filesystem is used, it
+      // may know whether inputs were lost. We should fail fast if any were; rewinding may be able
+      // to fix it.
+      checkActionFileSystemForLostInputs(actionExecutionContext, action, outputService);
+
+      return artifacts;
     } catch (ActionExecutionException e) {
+
+      // Input discovery failures may be caused by lost inputs. Lost input failures have higher
+      // priority because rewinding may be able to restore what was lost and allow the action to
+      // complete without error.
+      if (!(e instanceof LostInputsActionExecutionException)) {
+        try {
+          checkActionFileSystemForLostInputs(actionExecutionContext, action, outputService);
+        } catch (LostInputsActionExecutionException lostInputsException) {
+          e = lostInputsException;
+        }
+      }
+
       if (e instanceof LostInputsActionExecutionException) {
         // If inputs were lost during input discovery, then enrich the exception, informing action
         // rewinding machinery that these lost inputs are now Skyframe deps of the action.
@@ -1019,7 +1038,24 @@
       ActionContinuationOrResult nextActionContinuationOrResult;
       try (SilentCloseable c = profiler.profile(ProfilerTask.INFO, "ActionContinuation.execute")) {
         nextActionContinuationOrResult = actionContinuation.execute();
+
+        // An action's result (or intermediate state) may have been affected by lost inputs. If an
+        // action filesystem is used, it may know whether inputs were lost. We should fail fast if
+        // any were; rewinding may be able to fix it.
+        checkActionFileSystemForLostInputs(actionExecutionContext, action, outputService);
       } catch (ActionExecutionException e) {
+
+        // Action failures may be caused by lost inputs. Lost input failures have higher priority
+        // because rewinding may be able to restore what was lost and allow the action to complete
+        // without error.
+        if (!(e instanceof LostInputsActionExecutionException)) {
+          try {
+            checkActionFileSystemForLostInputs(actionExecutionContext, action, outputService);
+          } catch (LostInputsActionExecutionException lostInputsException) {
+            e = lostInputsException;
+          }
+        }
+
         boolean isLostInputsException = e instanceof LostInputsActionExecutionException;
         if (isLostInputsException) {
           ((LostInputsActionExecutionException) e).setActionStartedEventAlreadyEmitted();
@@ -1381,6 +1417,20 @@
   }
 
   /**
+   * Validates that all action input contents were not lost if they were read, and if an action file
+   * system was used. Throws a {@link LostInputsActionExecutionException} describing the lost inputs
+   * if any were.
+   */
+  private static void checkActionFileSystemForLostInputs(
+      ActionExecutionContext context, Action action, OutputService outputService)
+      throws LostInputsActionExecutionException {
+    FileSystem actionFileSystem = context.getActionFileSystem();
+    if (actionFileSystem != null) {
+      outputService.checkActionFileSystemForLostInputs(actionFileSystem, action);
+    }
+  }
+
+  /**
    * Validates that all action outputs were created or intentionally omitted. This can result in
    * chmod calls on the output files; see {@link ActionMetadataHandler}.
    *
diff --git a/src/main/java/com/google/devtools/build/lib/vfs/OutputService.java b/src/main/java/com/google/devtools/build/lib/vfs/OutputService.java
index 4420ad6..1fa759f 100644
--- a/src/main/java/com/google/devtools/build/lib/vfs/OutputService.java
+++ b/src/main/java/com/google/devtools/build/lib/vfs/OutputService.java
@@ -25,6 +25,7 @@
 import com.google.devtools.build.lib.actions.EnvironmentalExecException;
 import com.google.devtools.build.lib.actions.ExecException;
 import com.google.devtools.build.lib.actions.FilesetOutputSymlink;
+import com.google.devtools.build.lib.actions.LostInputsActionExecutionException;
 import com.google.devtools.build.lib.actions.MetadataConsumer;
 import com.google.devtools.build.lib.actions.cache.MetadataHandler;
 import com.google.devtools.build.lib.events.EventHandler;
@@ -181,6 +182,13 @@
       ImmutableMap<Artifact, ImmutableList<FilesetOutputSymlink>> filesets)
       throws IOException {}
 
+  /**
+   * Checks the filesystem returned by {@link #createActionFileSystem} for errors attributable to
+   * lost inputs.
+   */
+  default void checkActionFileSystemForLostInputs(FileSystem actionFileSystem, Action action)
+      throws LostInputsActionExecutionException {}
+
   default boolean supportsPathResolverForArtifactValues() {
     return false;
   }