multithreading - Windows Form UI Thread issue c# -

i have working application, except in one computer. in computer application crashes when savefiledialog opens. no errors, no exceptions.

after research found 1 way fix crash make savefiledialog in new thread.

static void open(object name) {     savefiledialog savefiledialog1 = new savefiledialog();     savefiledialog1.filter = "microsoft word document (.docx)|*.docx";     savefiledialog1.filterindex = 2;     savefiledialog1.restoredirectory = true;     savefiledialog1.title = "where save " + (string)name + " ? ";     try     {         th.isbackground = false;             boule = savefiledialog1.showdialog() == dialogresult.ok;         ptth = savefiledialog1.filename;                  }     catch (exception exc)     { messagebox.show(exc.message); } } 

i put in event:

thread th = new thread(new parameterizedthreadstart(open)); th.start("quotation"); 

the problem have error

current thread must set single thread apartment (sta) mode before ole...

so checked , have "[stathread]" before main. added line in "open" method:

th.setapartmentstate(apartmentstate.sta); 

but new error appear :

failed set specified com apartment state

what did wrong ? how make proper ui thread ? there easier way?

edit : it's more weird because in app use openfiledialog picture , works perfectly. issue savefiledialog? come else?

instead of starting new thread can set apartmentstate current ui thread.

var thread = new func<thread>(() => { return thread.currentthread; }).invoke(); thread.setapartmentstate(apartmentstate.sta);