After updating several other extensions Quote Media and BBFree data sets disappeared from the data tree. There is also no option to choose those data providers in the “Create a new Dataset” window even though both extensions are installed in the Extension Manager, while show Other Extension option is chosen.
I tried to uninstall and reinstall Quote Media Static provider 2012.05, but it did not help.
Please help to restore those datasets.

You appear to be using different editions of Wealth-Lab (Developer and Pro) on the same PC, and uninstalled some data provider (probably IQFeed or less likely ASCII) in WLP that requires the Market Manager, removing its DLL file. In this case, the providers will stay visible in the EM while they won't function properly.

Unfortunately, neither BBFree nor QuoteMedia providers can be used to reinstall the missing Market Manager library. Eventually, we'll make this happen after we launch our redesigned website - but not before.

Currently, you can restore the MM's DLL by...

1) installing the ASCII or IQFeed provider extensions OR
2) copying the missing WealthLab.DataProviders.MarketManager.dll file from Developer into WLP's main folder

...and restarting WLP.

P.S. While it's not directly related to the problem, I'd still like to mention that reinstalling an extension by clicking "Download" on the website does not guarantee that it will land in WLP's "Other extensions" list if different Wealth-Lab editions (32-bit/64-bit and/or WLP/WLD) are installed on the same PC. Check out this FAQ: Extension installed in Wealth-Lab Developer doesn't show up after restarting application. Dragging a downloaded extension's WLE file (or using «Open Extension's *.wle file...») is the proper way in this scenario.

Due to demise of the free data feed we have taken down the BBFree provider from the Extensions section.