If you get the 'Refactoring failed - Files still read-only' as follows:

for VS2012:
Please update 'Visual Studio Tools for Git' extension to the latest version (this issue was fixed since version 0.9.5.0 of this addin). You may do that via VS Extension Manager ("Tools | Extensions and Updates").
If the issue is still present after the update, please disable/remove the 'Visual Studio Tools for Git' extension from the Visual Studio.
for VS2013:
Please disable embedded GIT provider in Options: Tools | Options | Source Control | Plug-in selection | Select "None";

Big thanks to Ronnie Overby for noticing this ( blogpost).
Any update on this please? Still getting this error in R# 8.0 and Git Ext. 0.9.5.0 (VS 2012.3).
I am getting this same error on Visual Studo 2013, and you can't uninstall the Git tools, as now they are bundled in Visual Studio, and not an extension anymore.
How do we solve this problem?
@Giggio
Tools => Options => Source Control => Plug-in Selection
Set "Current source control plug-in" to "None".
If you use Git, use SourceTree as your client.
@T the GIT provider just switches on again every time when I open the solution, and it can't be disabled, is there another workaround for this?
I'm running into this in VS2013 with new projects. I have to add them to a Git repository before it will let me do refactorings like move class to a new file
Are there any plans to fix this bug?
I'm getting the same error when try to refactor files (very frustrating). Switching my source control plug-in to None is a work around for only so long...what's the eta on a perm fix?
@AlDass I'm not sure if JetBrains can fix this, it's a problem with the MS Git provider.
If you want to completely disable the GIT provider (I also had performance issues, hanging Visual Studio, especially with large projects and lot's of JavaScript/TypeScript files) with it follow the steps here:
http://stackoverflow.com/a/23512676/67910
Problem still exists with
Diasbling teh Git provider in teh Extension menu works just fine, but I hope that gets fixed very soon!
It is 2015 and this still happens in R# 9. I AM working with Git so I am not going to disable it, but this error is quite, quite annoying. So what's the status here.. is this going to get fixed?
I've just started experiencing this issue. We are using TFS not Git. I don't have any Git extensions installed.
Microsoft Visual Studio Professional 2012
Version 11.0.61030.00 Update 4
Microsoft .NET Framework
Version 4.5.51209
Installed Version: Professional
LightSwitch for Visual Studio 2012 04938-004-0033001-02468
Microsoft LightSwitch for Visual Studio 2012
Office Developer Tools 04938-004-0033001-02468
Microsoft Office Developer Tools
Team Explorer for Visual Studio 2012 04938-004-0033001-02468
Microsoft Team Explorer for Visual Studio 2012
Visual Basic 2012 04938-004-0033001-02468
Microsoft Visual Basic 2012
Visual C# 2012 04938-004-0033001-02468
Microsoft Visual C# 2012
Visual C++ 2012 04938-004-0033001-02468
Microsoft Visual C++ 2012
Visual F# 2012 04938-004-0033001-02468
Microsoft Visual F# 2012
Visual Studio 2012 Code Analysis Spell Checker 04938-004-0033001-02468
Microsoft® Visual Studio® 2012 Code Analysis Spell Checker
Portions of International CorrectSpell™ spelling correction system © 1993 by Lernout & Hauspie Speech Products N.V. All rights reserved.
The American Heritage® Dictionary of the English Language, Third Edition Copyright © 1992 Houghton Mifflin Company. Electronic version licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.
Visual Studio 2012 SharePoint Developer Tools 04938-004-0033001-02468
Microsoft Visual Studio 2012 SharePoint Developer Tools
ASP.NET and Web Tools 2012.3.41009
Microsoft Web Developer Tools contains the following components:
Support for creating and opening ASP.NET web projects
Browser Link: A communication channel between Visual Studio and browsers
Editor extensions for HTML, CSS, and JavaScript
Page Inspector: Inspection tool for ASP.NET web projects
Scaffolding: A framework for building and running code generators
Server Explorer extensions for Windows Azure Web Sites
Web publishing: Extensions for publishing ASP.NET web projects to hosting providers, on-premises servers, or Windows Azure
CodeMaid #114
CodeMaid is an open source Visual Studio extension to cleanup, dig through and simplify our C#, C++, F#, VB, XAML, XML, ASP, HTML, CSS, LESS, SCSS, JavaScript and TypeScript coding.
Written by Steve Cadwallader, for more information visit http://www.codemaid.net/
JetBrains ReSharper Platform 6 Build 6.0.20141219.120158 on 2014-12-19 12:56:02Z
JetBrains ReSharper Platform package for Microsoft Visual Studio. For more information about ReSharper Platform, visit http://www.jetbrains.com/resharper. Copyright © 2015 JetBrains, Inc.
Microsoft Team Foundation Server 2012 Power Tools 3.0
Power Tools that extend the Team Foundation Server integration with Visual Studio.
Microsoft Visual Studio Process Editor 1.0
Process Editor for Microsoft Visual Studio Team Foundation Server
NuGet Package Manager 2.6.40627.9000
NuGet Package Manager in Visual Studio. For more information about NuGet, visit http://docs.nuget.org/.
PreEmptive Analytics Visualizer 1.0
Microsoft Visual Studio extension to visualize aggregated summaries from the PreEmptive Analytics product.
ReadyRoll SQL Projects 1.10.0
Develop your databases 'online' and simplify deployment using ReadyRoll database projects.
Visit http://ready-roll.com for more information. Copyright © ReadyRoll Sql Pty Ltd. All rights reserved.
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Generate Sql Merge https://github.com/readyroll/generate-sql-merge
Menees Diff Controls http://www.menees.com/
Log4Net http://logging.apache.org/log4net/
Extended WPF Toolkit https://wpftoolkit.codeplex.com/
Code InfoBox VSX http://www.codeproject.com/Articles/55196/Code-InfoBox-Visual-Studio-Extension-VSX
SQL Server Data Tools 11.1.41025.0
Microsoft SQL Server Data Tools
TFS Auto Shelve 2.1
Create a shelveset for the latest version of all pending changes, automatically. Pending changes from the local TFS workspaces will be shelved to the TFS Server every "x" number of minutes when solutions are opened.
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I have the same problem with Resharper 9 and VS 2012, it says "Files still read-only:" and shows the corresponding .Designer.cs file of the control I'm editing even though it's not read only. I am using TFS, I do not have Git. Unless I can find a comfortable workaround I will have to stop using Resharper because of this.