Hi all,

I have a really old v7.2.0 umbraco site that I am trying to upgrade to the latest version. I have had all sorts of trouble trying to get out of 7.2. I am hoping that once I get to 7.3 I can jump straight to 7.7.

I can't go straight from 7.2 to 7.3 (see below) so I instead I go to 7.2.6 first (which works fine and with no issues). Then try for 7.3, which gets most of the way through before spitting out the following error:

"Lucene.Net.Index.CorruptIndexException: checksum mismatch in segments file"

 2018-04-11 17:13:57,775 [P170824/D4/T18] ERROR Umbraco.Core.UmbracoApplicationBase - An unhandled exception occurred
Lucene.Net.Index.CorruptIndexException: checksum mismatch in segments file
   at Lucene.Net.Index.SegmentInfos.FindSegmentsFile.Run(IndexCommit commit)
   at Lucene.Net.Index.SegmentInfos.FindSegmentsFile.Run()
   at Lucene.Net.Index.SegmentInfos.Read(Directory directory)
   at Lucene.Net.Index.IndexWriter.Init(Directory d, Analyzer a, Boolean create, Boolean closeDir, IndexDeletionPolicy deletionPolicy, Boolean autoCommit, Int32 maxFieldLength, IndexingChain indexingChain, IndexCommit commit)
   at Lucene.Net.Index.IndexWriter..ctor(Directory d, Analyzer a, Boolean create, MaxFieldLength mfl)
   at Examine.LuceneEngine.Providers.LuceneIndexer.WriterFactory(Directory d) in X:\Projects\Examine\Examine\src\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 1867
   at Examine.LuceneEngine.WriterTracker.<>c__DisplayClass7_0.<GetWriter>b__0(String s) in X:\Projects\Examine\Examine\src\Examine\LuceneEngine\WriterTracker.cs:line 44
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at Examine.LuceneEngine.WriterTracker.GetWriter(Directory dir, Func`2 factory) in X:\Projects\Examine\Examine\src\Examine\LuceneEngine\WriterTracker.cs:line 44
   at Examine.LuceneEngine.Providers.LuceneIndexer.CreateIndexWriter() in X:\Projects\Examine\Examine\src\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 1832
   at UmbracoExamine.BaseUmbracoIndexer.CreateIndexWriter()
   at Examine.LuceneEngine.Providers.LuceneIndexer.EnsureIndex(Boolean forceOverwrite) in X:\Projects\Examine\Examine\src\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 661
   at Examine.LuceneEngine.Providers.LuceneIndexer.RebuildIndex() in X:\Projects\Examine\Examine\src\Examine\LuceneEngine\Providers\LuceneIndexer.cs:line 749
   at UmbracoExamine.BaseUmbracoIndexer.RebuildIndex()
   at UmbracoExamine.UmbracoContentIndexer.RebuildIndex()
   at Umbraco.Web.WebBootManager.Complete(Action`1 afterComplete)
   at Umbraco.Core.UmbracoApplicationBase.StartApplication(Object sender, EventArgs e)
   at Umbraco.Core.UmbracoApplicationBase.Application_Start(Object sender, EventArgs e)

I have found this Our topic about it but with no information I don't know how to fix this. I am hosting the umbraco installation on Azure.

Any help appreciated!

NB: If I upgrade straight to 7.3 (or any version higher) the upgrade goes through but the resulting page is just white, no errors in the logs or the browser console. Even if I try to go to site/umbraco same white page, no errors.