The above error code 30045 primarily appears when you try to open office program on a Windows 10 computers which are previously running on Windows 8.1. It has been observed that this error needs to repair or a reinstall and you can read the below information for more knowledge.

How to Solve Microsoft Office Error Code 30045 (livesupportonlinechat.com)

error code 30045

Issue Type : Error Code 30045

office programs will not open at all and gives you an error code 1058-4. Even you get a different error code 30045 when you try to repair or uninstall. This is found on Windows 8.1 upgraded to 10 machines recently.
First do a disc clean up so that we can remove old-Microsoft office installation traces from your computer.

How to do disc-cleanup:-

Method-1 Creating shortcut

1. Right click on your computer home screen, Goto “new” in the list and select “Shortcut “.
2. After clicking on a shortcut, a command prompt window will open and type the command “cleanmgr.exe” in it and name as you like to remember it as a disc clean up shortcut button.
3. Then an icon will appear on your home screen, click on it and select the required disc to clean up. (Normally Softwares gets installed on DRIVE:C which is default here).
4. Then a list of folders will appear, select temp folder, recycle bin and proceed to clean up the disc.

Meanwhile, watch this video to follow above steps for a disc cleanup.

In Conclusion,

You can also ask for System repair Image support or some Recovery help, we also restore your computer to a point when it was working fine without any issues.