IBM i 7.3 upgrade

Carefully follow the instructions.
IBM i 7.3>IBM i and related software>Installing, upgrading, or deleting
IBM i and related software>Upgrading or replacing IBM i and related
software>Preparing to upgrade or replace IBM i software>Preparing the
system for IBM i software upgrade or replacement>Reviewing software PTF
(fix) requirements>Finding the latest PSP information
<snip>
review the Updates and PTFs section found in the IBM i and Related
Software Link outside information center developerWorks® website (
www.ibm.com/developerworks/ibmi/software).
</snip>
Yep, they're serious about that.
https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/IBM%20i%20and%20Related%20Software

<snip>
*** Attention Customers who have installed 7.2 database group ptf SF99702
level 11 or applied individual ptfs SI60308 or SI60333.

Following the install of R720 database group ptf SF99702 level 11 or apply
of individual ptf SI60308 or ptf SI60333, a flag in SQL views is
incorrectly set to indicate the view contains a system-time period. This
can cause a problem during the install of R730 Boss Option 1 when
recreating views built on SQL system catalogs.

To prevent this R730 installation failure, apply R720 PTF SI60586 which
includes a program (QQQFIXVW) to correct views built on SQL system
catalogs.

The best practice is to run this program "CALL QSYS/QQQFIXVW" in
restricted state prior to your upgrade to R730. This program will correct
all views built on SQL system catalogs and prevent a possible R730 upgrade
failure.
</snip>

Recovery if you ignore this:

You will get "Automatic installation not complete".
GO LICPGM
10. Display installed licensed programs
Will show 5770SS1 - 1 Extended Base Support as "*ERROR"

According to the 7.2 to 7.3 PTF cross reference
http://www-912.ibm.com/s_dir/sline003.nsf/2d3aff1c6b4d6ce086256453000d971e/1b4f2a200e87b7e686257f93007ea0a1?OpenDocument
ORIGIN ORIGIN TARGET TARGET
PRODUCT VRM PTF/FIX VRM PTF/FIX
------- ------- ------- ------ -------
5770SS1 V7R2M0 SI60586 V7R3M0 SI60602

Download and apply that PTF and follow it's instructions.
sndptford SI60586
INSPTF LICPGM((*ALL)) INSTYP(*DLYALL)
CALL QSYS/QQQFIXVW

GO LICPGM
11. Install licensed programs
Install option 1 again.
10. Display installed licensed programs
Will show 5770SS1 - 1 Extended Base Support as "*COMPATIBLE"

Rob Berendt