Here is the other method per one of our internal docs:

Option 2: Add PA, Wrapper and AV Agent GUIDS to the Windows Secure Repair White-list Registry Key.

This option is derived from Microsoft KB document: http://support.microsoft.com/kb/2918614

- Click Start, click Run, type regedit in the Open box, and then click OK.

(Back up the registry by clicking file, then export and exporting the registry to a location of your choice)

-Locate and then click the following sub-key in the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer

- On the Edit menu, point to New, and then click DWORD Value.

- Type SecureRepairPolicy for the name of the DWORD, and then press Enter.

- Right-click SecureRepairPolicy, and then click Modify.

- In the Value data box, type 2, and then click OK.

- Locate and then click the following subkey in the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer

- On the Edit menu, point to New, and then click Key.

- Type SecureRepairWhitelist for the name of the key, and then press Enter.

- Double-click the SecureRepairWhitelist key to open it.

- On the Edit menu, point to New, and then click String Value. Create String Values that contain the product codes (including braces {}) of the products that have to be added to the Safe Recipients list.

The following are the product codes which should be added for the PA, Wrapper and AV agent installations:

32-bit Workstations:

{458F24ED-DEB5-4729-81EE-B989CEA2C217} - AV Agent

{8997941F-78DD-4F98-BA5B-749F2D3C25D6} - Wrapper

{735EF746-77A8-44E8-821F-4C77F038AA90} - Platform Agent

64-bit Workstations:

{4C89867B-2E80-4B0D-87DB-1BD643D5EF5D} - AV Agent

{8997941F-78DD-4F98-BA5B-749F2D3C25D6} - Wrapper

{735EF746-77A8-44E8-821F-4C77F038AA90} - Platform Agent

-------------------------------------------------------------------------------------------------------------------------These string values need to be the name of the new string value under >>Installer.

32-bit Servers:

{A84E6630-FE81-4D1F-BBA0-4BFBCC1D9493} - AV Agent

{8997941F-78DD-4F98-BA5B-749F2D3C25D6} - Wrapper

{735EF746-77A8-44E8-821F-4C77F038AA90} - Platform Agent

64-bit Servers:

{B53661DC-CD94-4B14-B15F-D9DDCFF72558} - AV Agent

{8997941F-78DD-4F98-BA5B-749F2D3C25D6} - Wrapper

{735EF746-77A8-44E8-821F-4C77F038AA90} - Platform Agent

After those are created, try re-installing again.

For error IO overlap while installing Symantec Endpoint Protection. Done by Zachary on 5/28/15. Last known problem user was Carolyn,

(Using the above method has resolved the IO overlap error)