I just installed manjaro plasma and I got updates needed but it froze halfway so i cancelled. Now it is stuck on preparing and I cant install anything. (Just log out and log in it works.)
This is why it’s better to install large updates with pacman on a TTY.
If you wish others to help you, please provide enough information for them to work with; starting with system information as described (below). Additionally, the (full) output of the commands used; including any errors generated.
Please also follow the links (below) to learn the best way to ask for help, and how to present information such as command output, for example.
Selecting a suitable category for your topic is also important - the very little information you have given does not indicate anything related to “Software & Applications”.
The topic has been moved to a more appropriate category.
Never add “Solved” to the title of your created topics.
While that may be the procedure for some forums, the Manjaro forum (based on Discourse) provides a button under every post for that purpose.
Title edited to remove “Solved”.
It is expected that the post that gave the solution, or helped you the most to find one, be marked as the Solution. Note that the topic post (the first post) does not have the button; this is by design.
Lastly, your topic has been Unlisted (hidden from public view) while you edit the first post to create a more actionable request for Support, in keeping with forum guidelines. It will be Re-Listed when you’re done.
Regards.
Welcome to the Manjaro community
As a new or infrequent forum user, please take some time to familiarise yourself with Forum requirements, and the many ways to use the forum to your benefit:
Update Announcements
The Update Announcements contain important information and a Known Issues and Solutions section that should generally be checked before posting a request for support.
System Information
While information from *-fetch type apps might be fine for someone wishing to buy your computer, for Support purposes it’s better to ask your system directly; 
Output of the inxi command with appropriate parameters will achieve this (naturally, formatted according to forum guidelines) and will generally be more useful for those wishing to help:
inxi --filter --verbosity=8
or the short form:
inxi -zv8
- inxi man pages (Arch Manual)
Be prepared to provide output from other commands whenever asked. It’s equally important to provide as much actionable information as possible in your first post, rather than simply indicating there is a problem.