One of my customer sites, the user was facing login issues to the console. The transations fie was around 300GB and he deleted the file as the C drive was running low on space. Now he is unable to login to console. How can start a fresh transation log file and resolve this issue?

1) Stop the Symantec Endpoint Protection Manager and Symantec Embedded Database services.
2) Rename or delete the current sem5.log
3) Click Start > Run and type CMD then click OK
4) In the Command Prompt type:
    For 32-bit: CD C:\Program Files\Symantec\Symantec Endpoint Protection Manager\ASA\win32\
    For 64-bit: CD C:\Program Files(x86)\Symantec\Symantec Endpoint Protection Manager\ASA\win32\
5) Press Enter. This will change directories to the folder containing dbsrv11.exe.
6) To force the recreation of sem5.log, type:
    For 32-bit: dbsrv11 -f "C:\Program Files\Symantec\Symantec Endpoint Protection Manager\db\sem5.db"
    For 64-bit: dbsrv11 -f "C:\Program Files(x86)\Symantec\Symantec Endpoint Protection Manager\db\sem5.db"
7) Press Enter
8) Click Start > Run and type services.msc then click OK
9) Start the Symantec Endpoint Protection Manager and Symantec Embedded Database services

check this link

http://www.symantec.com/business/support/index?page=content&id=TECH178718

restart the SEPM

Restart the Database Service and login the console

See this article if restart not work

https://www-secure.symantec.com/connect/articles/symantec-endpoint-protection-manager-121-database-using-high-amount-hard-drive-space

Below is the step for the solution

If incase, you are unable to log on the the manager, you can recreate the sem5.log file to resolve the issue.

1) Stop SEPM and database services.

2) Rename / Delete the current log

3) Click Start, click on Run and Type "CMD" then click OK

4) In the Command Prompt type: "CD C:\Program Files\Symantec\Symantec Endpoint Protection Manager\ASA\win32\" and press Enter this will change directories to the folder containing dbsrv11.exe.

5) To force the recreation of sem5.log. Type: "dbsrv11 -f "C:\Program Files\Symantec\Symantec Endpoint Protection Manager\db\sem5.db" and press Enter

6) Click Start, click on Run and Type "services.msc" then click OK and start the Symantec Embedded Database Service

7) Start the Symantec Endpoint Protection Manager service.

To make the space in symantec follow the below

Low Disk Space issues encountered on systems running Symantec Endpoint Protection

Disk Space Management procedures for the SEPM

http://www.symantec.com/business/support/index?page=content&id=TECH96214

Check the thread

https://www-secure.symantec.com/connect/forums/semlog-file