diff --git a/MareSynchronosServer/MareSynchronosServer/Authentication/SecretKeyAuthenticationHandler.cs b/MareSynchronosServer/MareSynchronosServer/Authentication/SecretKeyAuthenticationHandler.cs
index f379dce..401117f 100644
--- a/MareSynchronosServer/MareSynchronosServer/Authentication/SecretKeyAuthenticationHandler.cs
+++ b/MareSynchronosServer/MareSynchronosServer/Authentication/SecretKeyAuthenticationHandler.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Security.Claims;
@@ -16,6 +17,7 @@ namespace MareSynchronosServer.Authentication
 {
     public class SecretKeyAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
     {
+        public static ConcurrentDictionary<string, object> IdentificationLocks = new();
         private readonly MareDbContext _mareDbContext;
         public const string AuthScheme = "SecretKeyAuth";
 
@@ -45,15 +47,26 @@ namespace MareSynchronosServer.Authentication
                 return AuthenticateResult.Fail("Failed Authorization");
             }
 
+            if (!IdentificationLocks.TryGetValue(charNameHeader, out var lockObject))
+            {
+                lockObject = new();
+                IdentificationLocks[charNameHeader] = lockObject;
+            }
+
             if (user.CharacterIdentification != charNameHeader)
             {
-                try
+                lock (lockObject)
                 {
-                    user.CharacterIdentification = charNameHeader;
-                    _mareDbContext.Users.Update(user);
-                    await _mareDbContext.SaveChangesAsync();
+                    try
+                    {
+                        user.CharacterIdentification = charNameHeader;
+                        _mareDbContext.Users.Update(user);
+                        _mareDbContext.SaveChanges();
+                    }
+                    catch (DbUpdateConcurrencyException)
+                    {
+                    }
                 }
-                catch (DbUpdateConcurrencyException) { }
             }
 
             var claims = new List<Claim> {
diff --git a/MareSynchronosServer/MareSynchronosServer/FileCleanupService.cs b/MareSynchronosServer/MareSynchronosServer/FileCleanupService.cs
index 46ca13d..c0fa1ee 100644
--- a/MareSynchronosServer/MareSynchronosServer/FileCleanupService.cs
+++ b/MareSynchronosServer/MareSynchronosServer/FileCleanupService.cs
@@ -44,12 +44,13 @@ namespace MareSynchronosServer
             _logger.LogInformation($"Cleaning up files older than {filesOlderThanDays} days");
 
             using var scope = _services.CreateScope();
-            var dbContext = scope.ServiceProvider.GetService<MareDbContext>();
+            var dbContext = scope.ServiceProvider.GetService<MareDbContext>()!;
 
             var prevTime = DateTime.Now.Subtract(TimeSpan.FromDays(filesOlderThanDays));
             var filesToDelete =
                 dbContext.Files.Where(f => f.LastAccessTime < prevTime);
             dbContext.RemoveRange(filesToDelete);
+            dbContext.SaveChanges();
             foreach (var file in filesToDelete)
             {
                 var fileName = Path.Combine(_configuration["CacheDirectory"], file.Hash);
@@ -59,9 +60,6 @@ namespace MareSynchronosServer
                     File.Delete(fileName);
                 }
             }
-
-            dbContext.SaveChanges();
-
             var allFiles = dbContext.Files;
             foreach (var file in allFiles)
             {
diff --git a/MareSynchronosServer/MareSynchronosServer/Hubs/ConnectionHub.cs b/MareSynchronosServer/MareSynchronosServer/Hubs/ConnectionHub.cs
index 7cf3e9a..35edb0d 100644
--- a/MareSynchronosServer/MareSynchronosServer/Hubs/ConnectionHub.cs
+++ b/MareSynchronosServer/MareSynchronosServer/Hubs/ConnectionHub.cs
@@ -21,7 +21,7 @@ namespace MareSynchronosServer.Hubs
 
             if (userId != null)
             {
-                Logger.LogInformation("Heartbeat from " + userId);
+                Logger.LogInformation("Connection from " + userId);
                 var user = (await DbContext.Users.SingleAsync(u => u.UID == userId));
                 return new LoggedInUserDto
                 {
diff --git a/MareSynchronosServer/MareSynchronosServer/Hubs/FilesHub.cs b/MareSynchronosServer/MareSynchronosServer/Hubs/FilesHub.cs
index 204a90c..1a7079d 100644
--- a/MareSynchronosServer/MareSynchronosServer/Hubs/FilesHub.cs
+++ b/MareSynchronosServer/MareSynchronosServer/Hubs/FilesHub.cs
@@ -42,6 +42,7 @@ namespace MareSynchronosServer.Hubs
         [Authorize(AuthenticationSchemes = SecretKeyAuthenticationHandler.AuthScheme)]
         public async Task<List<UploadFileDto>> SendFiles(List<string> fileListHashes)
         {
+            fileListHashes = fileListHashes.Distinct().ToList();
             Logger.LogInformation("User " + AuthenticatedUserId + " sending files");
             var forbiddenFiles = DbContext.ForbiddenUploadEntries.Where(f => fileListHashes.Contains(f.Hash));
             var filesToUpload = new List<UploadFileDto>();
@@ -51,10 +52,11 @@ namespace MareSynchronosServer.Hubs
                 Hash = f.Hash,
                 IsForbidden = true
             }));
-            var existingFiles = DbContext.Files.Where(f => fileListHashes.Contains(f.Hash)).ToList();
+            fileListHashes.RemoveAll(f => filesToUpload.Any(u => u.Hash == f));
+            var existingFiles = DbContext.Files.Where(f => fileListHashes.Contains(f.Hash));
             foreach (var file in fileListHashes.Where(f => existingFiles.All(e => e.Hash != f) && filesToUpload.All(u => u.Hash != f)))
             {
-                Logger.LogInformation("Needs upload: " + file);
+                Logger.LogInformation("User " + AuthenticatedUserId + " needs upload: " + file);
                 var userId = AuthenticatedUserId;
                 await DbContext.Files.AddAsync(new FileCache()
                 {
@@ -90,9 +92,26 @@ namespace MareSynchronosServer.Hubs
             var forbiddenFile = DbContext.ForbiddenUploadEntries.SingleOrDefault(f => f.Hash == hash);
             if (forbiddenFile != null) return;
             var uploadedFile = new List<byte>();
-            await foreach (var chunk in fileContent)
+            try
             {
-                uploadedFile.AddRange(chunk);
+                await foreach (var chunk in fileContent)
+                {
+                    uploadedFile.AddRange(chunk);
+                }
+            }
+            catch
+            {
+                DbContext.Files.Remove(relatedFile);
+                try
+                {
+                    await DbContext.SaveChangesAsync();
+                }
+                catch
+                {
+                    // already removed
+                }
+
+                return;
             }
 
             Logger.LogInformation("User " + AuthenticatedUserId + " upload finished: " + hash + ", size: " + uploadedFile.Count);
@@ -115,6 +134,7 @@ namespace MareSynchronosServer.Hubs
                 relatedFile.Uploaded = true;
                 relatedFile.LastAccessTime = DateTime.Now;
                 await DbContext.SaveChangesAsync();
+                Logger.LogInformation("File " + hash + " added to DB");
                 return;
             }
             catch (Exception ex)
diff --git a/MareSynchronosServer/MareSynchronosServer/Hubs/UserHub.cs b/MareSynchronosServer/MareSynchronosServer/Hubs/UserHub.cs
index 56985ea..0ee6403 100644
--- a/MareSynchronosServer/MareSynchronosServer/Hubs/UserHub.cs
+++ b/MareSynchronosServer/MareSynchronosServer/Hubs/UserHub.cs
@@ -69,37 +69,11 @@ namespace MareSynchronosServer.Hubs
             return AuthenticatedUserId;
         }
 
-        [Authorize(AuthenticationSchemes = SecretKeyAuthenticationHandler.AuthScheme)]
-        public async Task GetCharacterData(Dictionary<string, int> visibleCharacterWithJobs)
-        {
-            var uid = AuthenticatedUserId;
-            Dictionary<string, CharacterCacheDto> ret = new();
-            var entriesHavingThisUser = DbContext.ClientPairs
-                .Include(w => w.User)
-                .Include(w => w.OtherUser)
-                .Where(w => w.OtherUser.UID == uid && !w.IsPaused && visibleCharacterWithJobs.Keys.Contains(w.User.CharacterIdentification))
-                .ToList();
-            foreach (var pair in entriesHavingThisUser)
-            {
-                bool isNotPaused = await DbContext.ClientPairs.AnyAsync(w =>
-                    !w.IsPaused && w.User.UID == uid && w.OtherUser.UID == pair.User.UID);
-                if (!isNotPaused) continue;
-                var dictEntry = visibleCharacterWithJobs[pair.User.CharacterIdentification];
-
-                var cachedChar = await
-                    DbContext.CharacterData.SingleOrDefaultAsync(c => c.UserId == pair.User.UID && c.JobId == dictEntry);
-                if (cachedChar != null)
-                {
-                    await Clients.User(uid).SendAsync("ReceiveCharacterData", cachedChar.CharacterCache,
-                        pair.User.CharacterIdentification);
-                }
-            }
-        }
 
         [Authorize(AuthenticationSchemes = SecretKeyAuthenticationHandler.AuthScheme)]
         public async Task PushCharacterDataToVisibleClients(CharacterCacheDto characterCache, List<string> visibleCharacterIds)
         {
-            Logger.LogInformation("User " + AuthenticatedUserId + " pushing character data to visible clients");
+            Logger.LogInformation("User " + AuthenticatedUserId + " pushing character data to " + visibleCharacterIds.Count + " visible clients");
 
             var uid = AuthenticatedUserId;
             var entriesHavingThisUser = DbContext.ClientPairs
@@ -166,7 +140,7 @@ namespace MareSynchronosServer.Hubs
         [Authorize(AuthenticationSchemes = SecretKeyAuthenticationHandler.AuthScheme)]
         public async Task<List<string>> GetOnlineCharacters()
         {
-            Logger.LogInformation("User " + AuthenticatedUserId + " sent character hash");
+            Logger.LogInformation("User " + AuthenticatedUserId + " requested online characters");
 
             var ownUser = DbContext.Users.Single(u => u.UID == AuthenticatedUserId);
             var otherUsers = await DbContext.ClientPairs
diff --git a/MareSynchronosServer/MareSynchronosServer/MareSynchronosServer.csproj b/MareSynchronosServer/MareSynchronosServer/MareSynchronosServer.csproj
index c298b5e..3c6d037 100644
--- a/MareSynchronosServer/MareSynchronosServer/MareSynchronosServer.csproj
+++ b/MareSynchronosServer/MareSynchronosServer/MareSynchronosServer.csproj
@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="Bazinga.AspNetCore.Authentication.Basic" Version="2.0.1" />
+    <PackageReference Include="Karambolo.Extensions.Logging.File" Version="3.3.0" />
     <PackageReference Include="lz4net" Version="1.0.15.93" />
     <PackageReference Include="Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore" Version="6.0.6" />
     <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="6.0.6" />
diff --git a/MareSynchronosServer/MareSynchronosServer/Program.cs b/MareSynchronosServer/MareSynchronosServer/Program.cs
index c0fca89..c27f10b 100644
--- a/MareSynchronosServer/MareSynchronosServer/Program.cs
+++ b/MareSynchronosServer/MareSynchronosServer/Program.cs
@@ -1,8 +1,12 @@
+using System;
+using System.IO;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Hosting;
 using System.Linq;
+using System.Reflection;
 using MareSynchronosServer.Data;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
 
 namespace MareSynchronosServer
 {
@@ -36,6 +40,17 @@ namespace MareSynchronosServer
                 .UseConsoleLifetime()
                 .ConfigureWebHostDefaults(webBuilder =>
                 {
+                    webBuilder.UseContentRoot(AppContext.BaseDirectory);
+                    webBuilder.ConfigureLogging((ctx, builder) =>
+                    {
+                        builder.AddSimpleConsole(options =>
+                        {
+                            options.SingleLine = true;
+                            options.TimestampFormat = "yyyy-MM-dd HH:mm:ss ";
+                        });
+                        builder.AddConfiguration(ctx.Configuration.GetSection("Logging"));
+                        builder.AddFile(o => o.RootPath = AppContext.BaseDirectory);
+                    });
                     webBuilder.UseStartup<Startup>();
                 });
     }
diff --git a/MareSynchronosServer/MareSynchronosServer/Startup.cs b/MareSynchronosServer/MareSynchronosServer/Startup.cs
index d8666ca..f9d490d 100644
--- a/MareSynchronosServer/MareSynchronosServer/Startup.cs
+++ b/MareSynchronosServer/MareSynchronosServer/Startup.cs
@@ -39,7 +39,6 @@ namespace MareSynchronosServer
 
             services.AddSingleton<IUserIdProvider, IdBasedUserIdProvider>();
 
-
             services.AddDbContext<MareDbContext>(options =>
             {
                 options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"));
diff --git a/MareSynchronosServer/MareSynchronosServer/appsettings.json b/MareSynchronosServer/MareSynchronosServer/appsettings.json
index c7b5c17..b388893 100644
--- a/MareSynchronosServer/MareSynchronosServer/appsettings.json
+++ b/MareSynchronosServer/MareSynchronosServer/appsettings.json
@@ -1,6 +1,6 @@
 {
   "ConnectionStrings": {
-    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=aspnet-MareSynchronosServer-BA82A12A-0B30-463C-801D-B7E81318CD50;Trusted_Connection=True;MultipleActiveResultSets=true"
+    "DefaultConnection": "Server=(localdb)\\SQLEXPRESS;Database=mare;Trusted_Connection=True;MultipleActiveResultSets=true"
   },
   "Logging": {
     "LogLevel": {
@@ -9,20 +9,32 @@
       "Microsoft.Hosting.Lifetime": "Information",
       "MareSynchronosServer.Authentication": "Warning",
       "System.IO.IOException": "Warning"
+    },
+    "File": {
+      "BasePath": "logs",
+      "FileAccessMode": "KeepOpenAndAutoFlush",
+      "FileEncodingName": "utf-8",
+      "DateFormat": "yyyMMdd",
+      "MaxFileSize": 10485760,
+      "Files": [
+        {
+          "Path": "mare-<counter>.log"
+        }
+      ]
     }
   },
-  "UnusedFileRetentionPeriodInDays" : 7, 
-  "CacheDirectory":  "G:\\ServerTest", // do not delete this key and set it to the path where the files will be stored
+  "UnusedFileRetentionPeriodInDays": 7,
+  "CacheDirectory": "G:\\ServerTest", // do not delete this key and set it to the path where the files will be stored
   "AllowedHosts": "*",
   "Kestrel": {
     "Endpoints": {
       "Https": {
-        "Url": "https://+:5001",
+        "Url": "https://+:5000",
         "Certificate": {
           "Subject": "darkarchon.internet-box.ch",
-          "Store": "Root",
+          "Store": "My",
           "Location": "LocalMachine",
-          "AllowInvalid": false
+          //"AllowInvalid": false
           //          "Path": "", //use path, keypath and password to provide a valid certificate if not using windows key store
           //          "KeyPath": ""
           //          "Password": ""