Question: I'm trying to implement the new Windows 7 taskbar progress bar. I managed to get it to work with TBPF\_NORMAL state using the following code:

```
CoCreateInstance(CLSID_TaskbarList, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&taskbarList));

HRESULT c = taskbarList->SetProgressState(hWnd, TBPF_NORMAL);
if (c != S_OK) MessageBox("ERROR");
taskbarList->SetProgressValue(hWnd, 5, 10);

```

However if I try the exact same code with TBPF\_INDETERMINATE, it doesn't display anything and there's no error either:

```
CoCreateInstance(CLSID_TaskbarList, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&taskbarList));

HRESULT c = taskbarList->SetProgressState(hWnd, TBPF_INDETERMINATE);
if (c != S_OK) MessageBox("ERROR");

```

Does anybody know what could be causing this problem?

Answer: 
Okay, it looks like it was a problem with the configuration of my system. I post the answer here because it's not obvious why one progress bar animation would work but not another.

In System Properties / Performance Options, I had "Animations in the taskbar and Start Menu" disabled. This option apparently disables the "indeterminate" animation but not the regular one. By re-enabling the option, the indeterminate animation works.
This happened to me too. In the code, I have a Form A that shows a Form B (which Form B in the OnLoad event calls SetProgressState) and after that Form A calls the method Close to itself, and when it was in Indeterminate mode it didn't show anything!

Surpringsly, if I close first Form A and then show Form B, the problem is solved!

I hope this can help somebody having a headache with this.