diff --git a/src/ahriman/core/build_tools/sources.py b/src/ahriman/core/build_tools/sources.py
index 24f7fc14..93ba7e4e 100644
--- a/src/ahriman/core/build_tools/sources.py
+++ b/src/ahriman/core/build_tools/sources.py
@@ -416,7 +416,7 @@ class Sources(LazyLogging):
         else:
             patch.write(sources_dir / "PKGBUILD")
 
-    def read(self, sources_dir: Path, commit_sha: str, path: Path) -> str:
+    def read(self, sources_dir: Path, commit_sha: str, path: Path) -> str | None:
         """
         read file content from the specified commit
 
@@ -426,6 +426,10 @@ class Sources(LazyLogging):
             path(Path): path to file inside the repository
 
         Returns:
-            str: file content at specified commit
+            str | None: file content at specified commit if available
         """
-        return check_output(*self.git(), "show", f"{commit_sha}:{path}", cwd=sources_dir, logger=self.logger)
+        try:
+            return check_output(*self.git(), "show", f"{commit_sha}:{path}", cwd=sources_dir, logger=self.logger)
+        except CalledProcessError:
+            self.logger.exception("failed to read file %s at %s", path, commit_sha)
+            return None
diff --git a/src/ahriman/core/database/operations/changes_operations.py b/src/ahriman/core/database/operations/changes_operations.py
index 46f8c909..8ce16333 100644
--- a/src/ahriman/core/database/operations/changes_operations.py
+++ b/src/ahriman/core/database/operations/changes_operations.py
@@ -81,7 +81,7 @@ class ChangesOperations(Operations):
                 values
                 (:package_base, :last_commit_sha, :changes, :pkgbuild, :repository)
                 on conflict (package_base, repository) do update set
-                last_commit_sha = :last_commit_sha, changes = :changes, pkgbuild = :pkgbuild
+                last_commit_sha = :last_commit_sha, changes = :changes, pkgbuild = coalesce(:pkgbuild, pkgbuild)
                 """,
                 {
                     "package_base": package_base,
diff --git a/tests/ahriman/core/build_tools/test_sources.py b/tests/ahriman/core/build_tools/test_sources.py
index 51deb6e7..ab48105e 100644
--- a/tests/ahriman/core/build_tools/test_sources.py
+++ b/tests/ahriman/core/build_tools/test_sources.py
@@ -605,3 +605,12 @@ def test_read(sources: Sources, mocker: MockerFixture) -> None:
     check_output_mock = mocker.patch("ahriman.core.build_tools.sources.check_output", return_value="content")
     assert sources.read(Path("local"), "sha", Path("PKGBUILD")) == "content"
     check_output_mock.assert_called_once()
+
+
+def test_read_failed(sources: Sources, mocker: MockerFixture) -> None:
+    """
+    must return None in case if file cannot be read from commit
+    """
+    mocker.patch("ahriman.core.build_tools.sources.check_output",
+                 side_effect=CalledProcessError(1, ["command"], "error"))
+    assert sources.read(Path("local"), "sha", Path("PKGBUILD")) is None
diff --git a/tests/ahriman/core/database/operations/test_changes_operations.py b/tests/ahriman/core/database/operations/test_changes_operations.py
index cf130006..a089a7ab 100644
--- a/tests/ahriman/core/database/operations/test_changes_operations.py
+++ b/tests/ahriman/core/database/operations/test_changes_operations.py
@@ -53,3 +53,12 @@ def test_changes_insert_remove_full(database: SQLite, package_ahriman: Package,
     assert database.changes_get(package_ahriman.base).changes is None
     assert database.changes_get(package_python_schedule.base).changes is None
     assert database.changes_get(package_ahriman.base, RepositoryId("i686", database._repository_id.name)) == changes2
+
+
+def test_changes_insert_pkgbuild_preserve(database: SQLite, package_ahriman: Package) -> None:
+    """
+    must preserve existing pkgbuild when inserting changes without pkgbuild
+    """
+    database.changes_insert(package_ahriman.base, Changes("sha1", "change1", "pkgbuild1"))
+    database.changes_insert(package_ahriman.base, Changes("sha2", "change2", None))
+    assert database.changes_get(package_ahriman.base) == Changes("sha2", "change2", "pkgbuild1")