diff --git a/lldb/source/Core/Debugger.cpp b/lldb/source/Core/Debugger.cpp
--- a/lldb/source/Core/Debugger.cpp
+++ b/lldb/source/Core/Debugger.cpp
@@ -1164,11 +1164,11 @@
         flags |= File::eOpenOptionAppend;
       else
         flags |= File::eOpenOptionTruncate;
-      auto file = FileSystem::Instance().Open(
+      llvm::Expected<FileUP> file = FileSystem::Instance().Open(
           FileSpec(log_file), flags, lldb::eFilePermissionsFileDefault, false);
       if (!file) {
-        // FIXME: This gets garbled when called from the log command.
-        error_stream << "Unable to open log file: " << log_file;
+        error_stream << "Unable to open log file '" << log_file
+                     << "': " << llvm::toString(file.takeError()) << "\n";
         return false;
       }
 
diff --git a/lldb/test/API/commands/log/invalid-args/TestInvalidArgsLog.py b/lldb/test/API/commands/log/invalid-args/TestInvalidArgsLog.py
--- a/lldb/test/API/commands/log/invalid-args/TestInvalidArgsLog.py
+++ b/lldb/test/API/commands/log/invalid-args/TestInvalidArgsLog.py
@@ -15,3 +15,8 @@
     def test_disable_empty(self):
         self.expect("log disable", error=True,
                     substrs=["error: log disable takes a log channel and one or more log types."])
+
+    @no_debug_info_test
+    def test_enable_empty(self):
+        self.expect("log enable lldb all -f this/is/not/a/valid/path", error=True,
+                    substrs=["Unable to open log file 'this/is/not/a/valid/path': No such file or directory\n"])