diff --git a/NGitLab.Mock/Clients/LibGit2SharpExtensions.cs b/NGitLab.Mock/Clients/LibGit2SharpExtensions.cs
index d58a3845..6b86a8c8 100644
--- a/NGitLab.Mock/Clients/LibGit2SharpExtensions.cs
+++ b/NGitLab.Mock/Clients/LibGit2SharpExtensions.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using NGitLab.Models;
 
@@ -62,7 +63,25 @@ public static Models.CommitInfo ToCommitInfo(this LibGit2Sharp.Commit commit)
 
         internal static LibGit2Sharp.Commit GetLastCommitForFileChanges(this LibGit2Sharp.Repository repository, string filePath)
         {
-            return repository.Commits.QueryBy(filePath).FirstOrDefault()?.Commit;
+            try
+            {
+                return repository.Commits.QueryBy(filePath).FirstOrDefault()?.Commit;
+            }
+            catch (KeyNotFoundException)
+            {
+                // LibGit2Sharp sometimes fails with the following exception
+                // System.Collections.Generic.KeyNotFoundException: The given key '1d08df45e551942eaa70d9f5ab6f5f7665a3f5b3' was not present in the dictionary.
+                //    at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
+                //    at LibGit2Sharp.Core.FileHistory.FullHistory(IRepository repo, String path, CommitFilter filter)+MoveNext() in /_/LibGit2Sharp/Core/FileHistory.cs:line 120
+                //    at System.Linq.Enumerable.TryGetFirst[TSource](IEnumerable`1 source, Boolean& found)
+                //    at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
+                //    at NGitLab.Mock.Clients.LibGit2SharpExtensions.GetLastCommitForFileChanges(Repository repository, String filePath) in /_/NGitLab.Mock/Clients/LibGit2SharpExtensions.cs:line 65
+                //    at NGitLab.Mock.Repository.GetFile(String filePath, String ref) in /_/NGitLab.Mock/Repository.cs:line 485
+                //    at NGitLab.Mock.Clients.FileClient.Get(String filePath, String ref) in /_/NGitLab.Mock/Clients/FileClient.cs:line 77
+                //    at NGitLab.Mock.Clients.FileClient.GetAsync(String filePath, String ref, CancellationToken cancellationToken) in /_/NGitLab.Mock/Clients/FileClient.cs:line 125
+            }
+
+            return null;
         }
     }
 }
diff --git a/NGitLab.Mock/Repository.cs b/NGitLab.Mock/Repository.cs
index fb7183f9..9808a9c2 100644
--- a/NGitLab.Mock/Repository.cs
+++ b/NGitLab.Mock/Repository.cs
@@ -492,7 +492,7 @@ public FileData GetFile(string filePath, string @ref)
                 Ref = @ref,
                 BlobId = ((Blob)commit[filePath].Target).Id.ToString(),
                 CommitId = commit.Sha,
-                LastCommitId = repo.GetLastCommitForFileChanges(filePath).Sha,
+                LastCommitId = repo.GetLastCommitForFileChanges(filePath)?.Sha,
             };
         }