Windows 10 too big-AppData,Seagate dashboard,SxS

[kahoona]

Windows 10 is 223g. I only have 13.5g left.
One problem is in Users/app data which has 30.5g. I cannot access it to see what is in there but it contains Seagate dashboard has 6g of files. I don't think it should have even one on the c drive. It backs up to external. Can I remove them?
Another is ACD systems catalogues/200/default/Asset Dbf at 8g. ACD systems also had 5g of thumbnails which I deleted but they will return.
Apple Computers? Mobile Sync/Backup is 9g. Could be the Ipad but that has only 6g on it right now.
Windows/ SxS has 9g
I need to reduce it and I hate to remove things that I use at work to another drive to make room for this "stuff" any suggestions of a link to a good, safe guide to removing it?

 

[DeadRam]

The Windows SxS folder contains backed up Windows files in case you uninstall Windows updates. Don't remove this folder. Windows also backs up Windows files every time it does a major update in the Spring & Fall. These files are stored in C:\Windows.old and allow you to revert back to a previous version of Windows. You can delete C:\Windows.old if you are happy with your current version of Windows.

 

[RARRAF]

might help a bit https://www.jam-software.com/treesize_free/

 

[das_stig]

Old updates are kept in c:\windows\softwaredistribution\download and they can be safely deleted.

Temp files found in c:\windows\temp

 

[jojesa]

The AppData folder contains folders with settings and app related data from your Microsoft roaming account.
The folder is also used by some apps on your computer to save data. You already discovered some of the apps from Apple, ACD and Seagate.

If any of these app files are not required, you could delete the files or uninstall the application from Control Panel.
Also you could change the app settings so they don't backup files to that disk.

Also run Disk Cleanup to safely free up drive space.
Open Disk Cleanup, select the C: drive, click the Clean up system files button and select all entries under 'Files to delete' and click OK.

 

[kahoona]

Update: I ran Disc Cleanup and it helped. Then it got bigger again. Ckeanup kept saying it would remove, then had removed large amounts but the size did not reduce and Spacemonger showed it all still there. Restarts did not help. I reactivated a second SSD and moved some things like recycle, desktop,downloads and documents to it while keeping the shortcuts through the C drive. It helped a bit but still Windows 10 grew. I did all of the suggested things but none actually shrunk it. Then I cleaned up the registry. A little later I lost almost 100g of the files that should have been gone. It is fine now. Something must have been keeping it from purging it. Yay! I know that messing with the registry with things like CCCleaner is frowned upon but , with a backup, it really helped me.

 

[jojesa]

You must have a app backing up data to the drive.

 

[kahoona]

Sorry I forgot to conclude. I spent some time making Desktop and download type items stored in windows redirect to a second 250g ssd to save size which worked well. Then, days after I repeatedly used Disc cleanup without much size reduction the changes in the boot drive happened and C drive got smaller. If it is possible, I assume that Disc Cleanup did work but the results were not visible to me for a couple of days.