Try copying the tab(Means the space, copy it from data item where you have your string stored) and paste it in place of \t .
Replace([Data1],"" "","",""). this worked for me
Thanks
If replacing the space also doens't work, then it must be checked against the ASCII equivalent of \t.
Tyr the following approach:
string strWithTabs = ""here is a string\twith a tab"";
char tab = '\u0009';
String line = strWithTabs.Replace(tab.ToString(), """");