diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1ddcead0f..27cb7533a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,9 @@ Changelog
 
 NOTE: isort follows the [semver](https://semver.org/) versioning standard.
 
+### 5.0.8 July 11, 2020
+  - Fixed #1277 & #1278: New line detection issues on Windows.
+
 ### 5.0.7 July 9, 2020
   - Fixed #1306: unexpected --diff behavior.
   - Fixed #1279: Fixed NOQA comment regression.
diff --git a/isort/api.py b/isort/api.py
index 572bc5167..58367f3e0 100644
--- a/isort/api.py
+++ b/isort/api.py
@@ -396,14 +396,14 @@ def _sort_imports(
             if not line_separator:
                 line_separator = "\n"
         else:
-            if not line_separator:
-                line_separator = line[-1]
+            stripped_line = line.strip()
+            if stripped_line and not line_separator:
+                line_separator = line[len(line.rstrip()):]
 
             for file_skip_comment in FILE_SKIP_COMMENTS:
                 if file_skip_comment in line:
                     raise FileSkipComment("Passed in content")
 
-            stripped_line = line.strip()
             if (
                 (index == 0 or (index in (1, 2) and not contains_imports))
                 and stripped_line.startswith("#")
diff --git a/tests/test_regressions.py b/tests/test_regressions.py
index 3e288568e..8b751e318 100644
--- a/tests/test_regressions.py
+++ b/tests/test_regressions.py
@@ -224,3 +224,24 @@ def test_add_imports_shouldnt_move_lower_comments_issue_1300():
 ANSWER = 42
 """
     assert isort.code(test_input, add_imports=["from os import path"]) == test_input
+
+
+def test_windows_newline_issue_1277():
+    """Test to ensure windows new lines are correctly handled within indented scopes.
+    See: https://github.com/timothycrosley/isort/issues/1277
+    """
+    assert (
+        isort.code("\ndef main():\r\n    import time\r\n\n    import sys\r\n") ==
+        "\ndef main():\r\n    import sys\r\n    import time\r\n"
+    )
+
+
+def test_windows_newline_issue_1278():
+    """Test to ensure windows new lines are correctly handled within indented scopes.
+    See: https://github.com/timothycrosley/isort/issues/1278
+    """
+    assert isort.check_code(
+        "\ntry:\r\n    import datadog_agent\r\n\r\n    "
+        "from ..log import CheckLoggingAdapter, init_logging\r\n\r\n    init_logging()\r\n"
+        "except ImportError:\r\n    pass\r\n"
+    )