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technology02.png(__Updated Wednesday 30JAN2009.__) Developing applications that manipulate OpenOffice documents has always been rather tricky; not very difficult, but just tricky to get right.

With OpenOffice 3, things got trickier and applications that used to work will now fail.
I’ve just spend nearly a day trying to get a mail-merge application I built to work again with the new version of OO.
###Changes and limitations###
Developing .Net applications with OpenOffice 3 [now requires that the .Net framework 3.5 be installed][10].
Only one version of OpenOffice/StarOffice must be installed.

###Getting the CLI assemblies in your project###
OpenOffice used to ship with a bunch of CLI DLLs for manipulating Open Documents from .Net.
With OpenOffice version 3, these DLLs are directly installed in the GAC and not available in the Program installation folder any longer, making them unavailable when you need to add them as references to your Visual Studio project.

The trick is to extract the DLLs from the installation CAB, then reference those and make sure you exclude them in your setup file so only the latest version installed on the user’s computer’s GAC will get used.

1. Open the installation folder where the installation files are extracted (usually left on your desktop under a folder like ` 3.0 (en-US) Installation Files` during the OO installation process.
2. Open the `` file (using a utility like [7zip][7zip] if necessary) and extract the files matching `cli_*.dl`.
3. Add the ones you need to your VS Project’s references and make sure the properties of these references have their _Copy Local_ and _Specific Version_ properties set to _false_.
4. If you have a setup project that added these references to the list of files, right-click each of them and select _Exclude_ to make sure they won’t be packaged.

The reason for not deploying the DLLs is that they are very specific to a given OpenOffice version and the latest assemblies relevant to the user’s OpenOffice installation will already be deployed to the target machine’s GAC.
When .Net loads assemblies, if they are not included in the path of the application being launched, they will be loaded from the GAC if they can be found there.

###Path and environment setup###
Before being able to call OpenOffice from your application you now must set your application’s environment variables to the correct paths so the assemblies can find the actual OpenOffice library and program files.

Basically, you need to add to your `PATH` the path to the folder where the UNO java libraries reside.
You also need to add a `UNO_PATH` environment variable that points to the program folder of OpenOffice.
Basically, before any call to OpenOffice functions you must:

* Append to `PATH` something like `C:\Program Files\ 3\URE\bin`.
* Create a `UNO_PATH` variable set to `C:\Program Files\ 3\program`.

Because there is no guarantee that these paths will not change or are valid for all systems you must get them from specific keys located in the Registry:

* `PATH` is appended with the vaue of `HKLM\SOFTWARE\\Layers\URE\1\UREINSTALLLOCATION` to which you must append the `bin` directory.
* `UNO_PATH` is set to the content of the `HKLM\SOFTWARE\\UNO\InstallPath` key.

See the C# and VB.Net code below for working examples.

###Special Considerations for x64 systems###
My development machine runs Windows Server 2008 x64 and I’ve ran into some specific issues that you’re likely to encounter when deploying to a 64 bits OS.

__OpenOffice is 32 bits only__
That means that your .Net project must be set to target x86 systems only:
Open your Solution’s _Configuration Manager_ and under _Active solution platform_ click _New…_ then:


Make sure you repeat this for both the _Debug_ and _Release_ configurations.

__Registry keys are elsewhere__
32 bit applications see their registry keys normally expected under:
`HKEY_LOCAL_MACHINE\Software` moved to:
`HKEY_LOCAL_MACHINE\Software\Wow6432Node` instead.
This of course creates issues when you’re trying to read a registry key that’s not where it should be…

###The Code###
The code below will allow you to correctly connect to OpenOffice 3 under 32 or 64 bit systems.
It reads the registry to find the proper paths and appends the `PATH` and creates the `UNO_PATH` environment variables expected by the the bootstrapper to find the OpenOffice program and libraries.

The code is built upon information and a test program made available by [Marten Feldtmann][1] on his [blog][2] (more information, in English, is available on [OOoForum][3] ).

Please let me know if this works for you or if you have any corrections.

private void InitOpenOfficeEnvironment() {
string baseKey;
// OpenOffice being a 32 bit app, its registry location is different in a 64 bit OS
if (Marshal.SizeOf(typeof(IntPtr)) == 8)
baseKey = @”SOFTWARE\Wow6432Node\\”;
baseKey = @”SOFTWARE\\”;

// Get the URE directory
string key = baseKey + @”Layers\URE\1″;
RegistryKey reg = Registry.CurrentUser.OpenSubKey(key);
if (reg==null) reg = Registry.LocalMachine.OpenSubKey(key);
string urePath = reg.GetValue(“UREINSTALLLOCATION”) as string;
urePath = Path.Combine(urePath, “bin”);

// Get the UNO Path
key = baseKey + @”UNO\InstallPath”;
reg = Registry.CurrentUser.OpenSubKey(key);
if (reg==null) reg = Registry.LocalMachine.OpenSubKey(key);
string unoPath = reg.GetValue(null) as string;

string path;
path = string.Format (“{0};{1}”, System.Environment.GetEnvironmentVariable(“PATH”), urePath);
System.Environment.SetEnvironmentVariable(“PATH”, path);
System.Environment.SetEnvironmentVariable(“UNO_PATH”, unoPath);

In VB.Net:

Private Sub InitOpenOfficeEnvironment()
Dim baseKey As String
‘ OpenOffice being a 32 bit app, its registry location is different in a 64 bit OS
If (Marshal.SizeOf(GetType(IntPtr)) = 8) Then
baseKey = “SOFTWARE\Wow6432Node\\”
baseKey = “SOFTWARE\\”
End If

‘ Get the URE directory
Dim key As String = (baseKey + “Layers\URE\1”)
Dim reg As RegistryKey = Microsoft.Win32.egistry.CurrentUser.OpenSubKey(key)
If (reg Is Nothing) Then
reg = Registry.LocalMachine.OpenSubKey(key)
End If
Dim urePath As String = CType(reg.GetValue(“UREINSTALLLOCATION”),String)
urePath = Path.Combine(urePath, “bin”)

‘ Get the UNO Path
key = (baseKey + “UNO\InstallPath”)
reg = Microsoft.Win32.Registry.CurrentUser.OpenSubKey(key)
If (reg Is Nothing) Then
reg = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(key)
End If
Dim unoPath As String = CType(reg.GetValue(Nothing),String)

Dim path As String
path = String.Format (“{0};{1}”,System.Environment.GetEnvironmentVariable(“PATH”),urePath)
System.Environment.SetEnvironmentVariable(“PATH”, path)
System.Environment.SetEnvironmentVariable(“UNO_PATH”, unoPath)
End Sub

07MAY2009 – Added reference link to OOo documentation.
03DEC2008 – Added VB.Net translation. Thanks to Stefan for suggesting it.
30JAN2009 – Added reference to Aleksandr Sazonov’s article on CodeProject (thanks for the the article).


* [CLI Language Binding][cli]
* [OOoForum thread][forum1] on getting sample C# code to work with OpenOffice 3
* [OOoForum thread][3] on upgrading code from OpenOffice 2.4 to 3
* [Programming with .Net quick start guide][quickstart].
* [CLI UNO bridge not working][3]
* [Cross-compatible spreadsheet processor][4] in .Net for Excel and OOo Calc, article from Aleksandr Sazonov on CodeProject.
* [Writing client programs – from the OOo documentation][5]

[CM]: /wp-content/uploads/2008/11/sshot-4.png
[0]: /2008/mac-installing-windows-server-2008-x64-on-a-macbook-pro/

Last modified: Sunday, 18 April 2021



Hi. Thanks heaps for this article – you saved my bacon. After upgrading to OO3 our windows service no longer work… but then I found your article and the tip on the UNO_PATH and now its all working. Thanks again.

@Georges: you’re welcome, thanks for reporting back.

Thanks, that helped a lot! I needed a VB.NET version and I like to share it for others to copy-paste. ' Don't know how to do this with VB '// OpenOffice being a 32 bit app, its registry location is different in a 64 bit OS 'if (Marshal.SizeOf(typeof(IntPtr)) == 8) then ' baseKey = "SOFTWARE\Wow6432Node\\"; 'Else 'End If '// so just assume 32bit Dim baseKey As String baseKey = "SOFTWARE\\" '// Get the URE directory Dim key As String = baseKey + "Layers\URE\1" Dim reg As Microsoft.Win32.RegistryKey reg = Microsoft.Win32.Registry.CurrentUser.OpenSubKey(key) If (reg Is Nothing) Then reg = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(key) Dim urePath As String = reg.GetValue("UREINSTALLLOCATION").ToString reg.Close() urePath = System.IO.Path.Combine(urePath, "bin") '// Get the UNO Path key = baseKey + "UNO\InstallPath" reg = Microsoft.Win32.Registry.CurrentUser.OpenSubKey(key) If (reg Is Nothing) Then reg = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(key) Dim unoPath As String = reg.GetValue(Nothing).ToString reg.Close() Dim path As String path = String.Format("{0};{1}", System.Environment.GetEnvironmentVariable("PATH"), urePath) System.Environment.SetEnvironmentVariable("PATH", path) System.Environment.SetEnvironmentVariable("UNO_PATH", unoPath)

Thanks for the code Stefan. I’ve added a VB.Net translation to the article.

I have the same bootstrap hanging problem. I am using the code you have provided to retrieve the proper path settings, however, the bootstrapper still hangs on my deployed server. I am using a webservice ( to create a calc document and saving it to file. The webservice runs properly when tested locally on my development box but hangs when I deploy to the server. Both the server and my box have OOo 3. I notice that the soffice.exe and soffice.bin processes both get started on the server. I read here that the problem may have to do with the aspnet account being used to start the OOo service. Even after setting the webservice to impersonate a valid user with the required permissions, the bootstrapper still hangs. The server OS is MS Windows Server 2003 SP2.

I found further information about my problem HERE. It looks like the problem may have to do with .net 2.0. I will try building my webservice with .net 1.1 and see if that helps

Hi. Thanks for the sample. I Used it to upgrade my OOo library from OO 2.x to 3.0. Code sample and a bit of description at If you consider this is an adverisement, feel free to block it.

Hi Aleksandr, thanks for the CodeProject article. I updated this post to include it as a reference. Your project is actually something I was actually needing so I’ll most probably end up using it myself.

Hey! Thank u so much for the code man it helped me a lot:)

My application when run in (Server) Environment and produce oo report. It producing Open Office Excel file and Charts. Its OK. (B) In IIS Server it not produce the file and processing goes endless. Not produce any error / exception. When wait long for localhost it shows “An un handeled exception(System.CannotUnloadAppDomainException) occured in aspnet_wp.exp” What I have done. OpenOffice 3.o Added the TblProc.dll as reference in my project. five cli_ files are in GAC Excluding cli_uno.dll file give HResult error when add cli_uno.dll as reference so not added in project and it is not in GAC and in VS Server without it producing file. Please suggest what I do to resolve this issue.

Developing .Net applications with OpenOffice 3 now requires that the .Net framework 3.5 be installed. I have a client, which is using .NET 2.0, it manages to work with OOo 3.0. Is it a requirement of OOo itself – to have .NET 3.5 installed or just a typo? I made no tests on a machine without fw 3.5.

@Aleksandr: this is what the OpenOffice wiki for .Net binding says (cached version, I’m having trouble accessing the site). I’m not sure which part of the .Net Framework 3.5 is required. Best is to test thoroughly.

OpenOffice 3.0 works fine with .Net Framework 2.0. Running the site from IIS Server need some access rights as ASPNET worker process can not access local machine files.

I had problems with starting OpenOffice 3.1 remotely from .NET 3.5 via TCP until i realized this: I used Visual Studio 2008 and my .NET-Programm was a Windows-Service with his own app.config-File. My first and fatal step during my tests was, that i changed the .NET-runtime in my project-properties to .NET 2.0 . Therefore VS2008 inserted ohne row in my app.config-File, which tells my program, to use .NET 2.0 at runtime. After i read this article, i changed the .NET-runtime to .NET 3.5 and it don’t run. I don’t realize, that this single line in my app.config-File wasn’t removed and therefore my program used .NET 2.0 at runtime anymore. When i realized this line and removed it, so that my program used realy .NET 3.5, in runs perfect!

I have done all the above mensioned things but getting error “External component has thrown an exception.” for bootstrap. code line is XComponentContext oStrap = uno.util.Bootstrap.bootstrap() ; please help

hI , InitOpenOfficeEnvironment() function works for me to resolve the bootstrap error. Thanks!

Pawan Kumar 

I would appreciate dot net developer who used open office to produce excel reports deployed over web Server IIS. I m still facing the problem as this code works well in my developement environment ASP.Net 2.0 on my machine, But fails to produce report when deployed on web server (IIS). I would like to thanks if some one provide me complete code of this for Visual Studio 2005 to produce reports in scalc.

It s very helpful text. Nowhere else could not find something for the cli dll’s of OpenOffice 3 and i could n t do anything. Thank s a lot!!!!

Hi. It’s very helpful article. But I Can’t deploy project using OO CLI to x64 production machine. Is there any help for deploing project to x64 server. Thanks in advance

Illés András 

Hi! Thanks for your article! Do you have any experience with oo 3.3? After your help the problem is still on. 🙁 An very dummy question but: what means GAC abbrevation? Best Regards! Andris

Hi, I am facing the problem that the code is hanging infinitely at calling Bootstrap.bootstrap(). I have tried many solution and the ones suggested here but all in vain. Additional specification of my working environment: – I am having Windows 7 Ultimate OS – I am using Visual Studio 2008 – The code is written in 3.5 website The surprising part is that things are working fine in ASP.NET Web Application but giving problem in ASP.NET Web Site. Please let me know, if I am missing something. Thanks..

Shital Akruwala 

thank u….u helped a lot in finding cli*.dll files…

i m getting an error of specified module not found,plz do tell me how to resolve this error

thanks a lot.

Hi Iam Using open office in my project for generating pdf files for .docx,.xlsx file by using UNO DLLS I m facing the problem as this code works well in my developement environment ASP.Net on my machine, But not getting output (no response browser running for long time but no result) when deployed on web server (IIS). can any tell how to do it through IIS Thanks In Advance

had to change the line string key = baseKey + @"Layers\URE\1"; to string key = baseKey + @"Layers_\URE\1"; in ConfigureOO3x to get this to work for me

Artjoms Fomenko 

Big thanks to you’r post it was really helpfull! Specially thanks for the Platform configuration. And about this code: ' OpenOffice being a 32 bit app, its registry location is different in a 64 bit OS If (Marshal.SizeOf(GetType(IntPtr)) = 8) Then baseKey = "SOFTWARE\Wow6432Node\\" Else baseKey = "SOFTWARE\\" End If IntPtr.Size won’t return the correct value if running in 32-bit .NET Framework 2.0 on 64-bit Windows (it would return 32-bit). USE THIS INSTEAD: [DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)] #region DLL import to find bit version [return: MarshalAs(UnmanagedType.Bool)] public static extern bool IsWow64Process([In] IntPtr hProcess, [Out] out bool lpSystemInfo); #endregion #region Windows bit version finding public static bool Is64Bit() { bool retVal; IsWow64Process(Process.GetCurrentProcess().Handle, out retVal); return retVal; } public static string GetOSBit() { bool is64bit = Is64Bit(); if (is64bit) return "x64"; else return "x32"; } #endregion

Hi, great solution! Has anybody have any experiences doing this with OO (Open Office) 4.1 and .NET 4? It works fine localy, but not when published to IIS although OO process is started. Br, Tadej

I get this runtime error: An unhandled exception of type ‘System.NullReferenceException’ occurred in Complete_Text_Editor.dll Additional information: Object reference not set to an instance of an object. That points to this line in Dim urePath As String = CType(reg.GetValue(“UREINSTALLLOCATION”), String)

Is it possible to read Base OpenOffice .odb database (tables, views, queries) from .Net application?

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