Reverted BIOS to default, now don’t have GRUB?

I have a lenovo laptop with Windows 10. Some time later I installed Ubuntu on this laptop and could choose whether I wanted to use Windows or Ubuntu from GRUB. Today something strange happened, I turned on my PC as usual, but instead of GRUB menu I saw Lenovo Boot Manager with options Windows, Ubuntu and HDD, all of them sent me back to this Boot Manager.

I went to BIOS and set all settings to default. After that Lenovo finally loaded, but I don’t have GRUB, Window is just loaded like Ubuntu was’t installed at all.

How can I restore GRUB or at least delete it together with Ubuntu to reinstall them later?

Screen resolution reverted to 800×600 after first software update on Lubuntu 18.04.2 LTS

I have just installed Lubuntu 18.04.2 LTS on my 9-yearold Acer Aspire 5630 laptop with Intel graphics.Screen resolution 1280×1024 was OK with Live CD and on installed OS until first Software Update this morning (15 April ’19).If I issue xrandr command from terminal the correct resolution is shown at the top of the list and is shown as being selected. I can restore correct resolution with xrandr -c 0. I didn’t use any updates during installation. I have repeated installation with similar results.

Understanding ‘Access Denied’ so that permissions can be reverted – icacls and takeown


  • Before taking ownership of files and folders I would like to understand how to view the current permissions so that they may be reverted.
  • I am reciving an ‘Access Denied’ message to view or save permissions with elevated command prompt for location: C:\ProgramData\Microsoft\Windows\SystemData in Windows 10 enviroment.
  • It looks like that I may need to take ownership first, then can view the permissions.

If I try to save an ACL file:

C:\Windows\system32>icacls C:\ProgramData\Microsoft\Windows\SystemData /save "C:\SystemData.acl" /t C:\ProgramData\Microsoft\Windows\SystemData: Access is denied. Successfully processed 0 files; Failed processing 1 files 

If I try to view permissions:

C:\Windows\system32>icacls "C:\ProgramData\Microsoft\Windows\SystemData" C:\ProgramData\Microsoft\Windows\SystemData: Access is denied. Successfully processed 0 files; Failed processing 1 files 

In the answer to ‘Understanding how to use Icals & Takeown’ the owner of the folder was NT SERVICE\TrustedInstaller which may infact may be a standard in Windows 10, though I am only guessing.

I do not know the owner to reset to with out taking ownership first:

takeown /f C:\ProgramData\Microsoft\Windows\SystemData /r icacls C:\ProgramData\Microsoft\Windows\SystemData /grant "%USERDOMAIN%\%USERNAME%":(F) /t Make Changes icacls C:\ProgramData\Microsoft\Windows\SystemData /setowner "??" /t icacls C:\ProgramData\Microsoft\Windows\SystemData /remove:g "%USERDOMAIN%\%USERNAME%":(F) /t 

In the answer to ‘Understanding how to use Icals & Takeown’ once taking ownership of folder, I see that the prior owner is still listed, so I may not need to know the permissions before taking ownership also, but just revert it to the second listed (F) owner.

C:\Windows\Web %USERDOMAIN%\%USERNAME%:(F)                NT SERVICE\TrustedInstaller:(F)  (REVERT TO THIS)                NT SERVICE\TrustedInstaller:(CI)(IO)(F)                NT AUTHORITY\SYSTEM:(M)                ... 

Likewise the alternative method for saving out an ACL in the anwser to ‘Understanding how to use Icals & Takeown’ I see that you would need to take ownership of folder and files before saving out an ACL so would have to revert permissions afterwards? This is a bit messed up but something like this?

takeown /f C:\ProgramData\Microsoft\Windows\SystemData /r     icacls C:\ProgramData\Microsoft\Windows\SystemData /save "C:\SystemData.acl" /t icacls C:\ProgramData\Microsoft\Windows\SystemData /grant "%USERDOMAIN%\%USERNAME%":(F) /t Make Changes icacls C:\ProgramData\Microsoft\Windows /restore "C:\SystemData.acl" icacls C:\ProgramData\Microsoft\Windows\SystemData /setowner "??" /t 

Reading:

Understanding how to use Icals & Takeown to make changes and reset in Windows 10

Create List of Access Denied Files & Folders

Setting Deny Permissions with ICACLS on “This Folder”

SU – Is there a way in which I can use takeown to apply ownership to every directory on the drive?

SU – Takeown grant permission

SS46 – Takeown

SS64 – Icacls