Follow step by step for IAR Embedded Workbench for MSP430 installation.
And these installation are similar to other device of IAR Embedded Workbench.
The Version of IAR on this example, which I install, is 5.60.

Click Install IAR Embedded Workbench

Make sure your remove USB dongles (IAR license USB) from your PCs.

Before we can use IAR, it has to activate license, this process need the internet.

Click Yes, for extract files of IAR Libary Source for 430

Click License then Activate Licese

Fill your license number 12 digit with “–“

If you licese activa correcly, it will show green color on the licese

After finish activate IAR license you can use IAR without internet connection.

We finish install IAR MSP 430 now you can test by compile project, if it work it will can compile.