Based on your post I am unclear as to whether the files (schematic and libraries) actually are missing from your computer or wherever they are stored OR if the CircuitStudio project is reporting them as missing and cannot locate them.
If the files exist on your computer, you should be able to add them again as existing files to your project. If the files are in fact no longer there or are corrupted and cannot be read in, then you would need to use your backups or perhaps check the history folder of your CircuitStudio project.
I think once you save the project again the reported missing files go away.
First thing to do is probably make a back up copy of your project folder structure so you can protect yourself from further corruption as you try to recover.
Good luck and sorry to hear about your problems.
We see this issue when we take the schematics, compile it and take it to the PCB layout editor.
When we go back, sometimes the components in the schematics page are missing.
Shall send you the snapshots next time when this issue occurs.
Thanks for the support.
What you newly describe is different than lost information due to a power outage.
I have not experienced unexplained removal of parts otherwise.
I know that CircuitStudio and Altium Designer, will remove (delete) parts on a PCB if they are not on the schematic as part of updating the PCB from the schematic. You must check the proper boxes in the process steps to prevent removal. There may be something similar when you update schematics from the PCB as you would do when back annotating the schematics from the PCB.
For example, if you put mounting holes or fiducials on the PCB and they are not in the schematic then they may be removed. If you forget about this you may make a PCB without the mounting holes. Therefore, I would recommend making schematic symbols for mounting holes, fiducials, test points and such that you want to ensure stay synchronized.
There is an optional setting in software to disable this automatic removal. Other users may find this better for them. To find this, open the options for the project and find the ECO Generation tab and the Remove Components item. Change it from Generate Change Orders to Ignore Differences. There may be other settings you want to customize for your use.
You can get to this from the tool ribbon Project > Options or go to the search window and type project options
Hopefully, this helps you.
I am using Circuit Studio 1.5.2 version.
During power outages, some schematics are missing or details are not displayed even though the project is compiled, saved.
Some component libraries are missing after a power outage or a PC reboot, despite all of them being compiled and saved previously.
Would request Circuit Studio experts to suggest a solution.