Update: If you use Microsoft Office 2010, you have to use other fix:

http://support.microsoft.com/kb/841215

• My Central Admin was gone
• All SharePoint sites were gone (also checking in IIS)

That may be a real shocker. One option is to simply rerun config wizard to have the Central admin site and restore entire farm from backup (you DO have backup, do you?). Otherwise here’s the process on how I recovered all the sites:

Re-run SharePoint Products and Technologies Configuration Wizard

1. Run the SharePoint Products and Technologies Configuration Wizard
2. Rejoin the existing farm (entering database server and configuration database and farm passphrase of your lost SharePoint farm) – thank God these aren’t deleted
3. Central admin site has to be recreated

After the configuration wizard has finished you should see all your web applications back in IIS

Remake manual changes to web.config files

If you were making manual changes (not through SharePoint Object Model) to web.config files of your web applications, these are lost, so you better keep track and remake those changes.

Restart services

Event though you may have your sites back there is still work to do. If you have custom solutions deployed to SharePoint, you have to re-deploy them. Fortunately these are still stored in SharePoint.

SharePoint service applications are not started and you may receive an error like "There are no addresses available for this application" (in logs, event viewer and of course in the web application.

1. In SharePoint central administration open Application Management
2. Under Service Applications select Services on Server
3. Click Start next to service applications that you wish to restart.

You will also notice virtual applications reappearing in your IIS under your SharePoint Services IIS site.

Redeploy solutions

OMG, also solutions are gone from web applications. Yes you need to re-deploy these as well.

1. In SharePoint Central Administration select System Settings
2. Select Manage Farm solutions
3. You will see that all solutions are (probably) there but none of them is deployed.
4. Deploy each solution as needed by selecting the solution and clicking “Deploy solution” and following steps.

Review

After redeploying check your web applications if everything is working correctly. I noticed even though solutions were not deployed, the data, configuration and permissions remained.

Re-running the SharePoint Products and technologies Configuration Wizard repaired the issue for me.

g_ExpGroupXSLTQueue is undefined

Microsoft has issued a hotfix for this bug. You can request it here:

http://support.microsoft.com/kb/2553117/en-us

There is a setting in SPD to fix that. In Tools menu select Page editor options

And under Code Formatting decrease the value in Indent property or change to spaces.

1. Change all Date and Time columns to single line of text and then back to Date and Time. Don’t worry, the data in these columns will be preserved.

2. There is a Microsoft Post-SP1 hotfix available here. It doesn’t fix lists that already have this issue though

3. If you export data to from SharePoint 3.0 / 2007 to Excel 2003 you might be getting this kind of error

4. If you’re exporting multiple choices field to Excel 2003

5. If you rename a Date and Time column this error may occur. Create an additional column and copy-paste values in a DataSheet view from one column to the new one

6. Changing the default date for Date and Time column from "Today" to "None" and then back may resolve the issue

All of the above solutions still didn’t work for me. What did the trick was following:

7. Lookup column points to a calculated field. Changed the lookup column to not point to calculated field but to a Single Line of Text field and the problem went away.