Lazarus component installation from Castle Editor doesn't seem to work

[michalis]

I am attaching a screenshot anyway but looking at the log file I realized that the editor did not have the writing privileges. In my case I solved it by running the editor in Administrator mode (on windows 10).

Aha, OK! Looking at source code, the cryptic “Failed to execute : 740” is from FPC implementation of TProcess on Windows (fcl-process/src/win/process.inc). They do Raise EProcess.CreateFmt(SErrCannotExecute,[FCommandLine,GetLastError]); and

• FCommandLine is empty (I guess because TProcess.CommandLine got deprecated some time ago, in favor of TProcess.Parameters list (and from CGE we indeed use new, non-deprecated TProcess.Parameters))

• and for some reason they just show an error number, not String message (I think SysErrorMessage would give the right message).

So we end up with cryptic “Failed to execute : 740”. Fixing this would require a fix from FPC side (do you want to submit a report to them?), to use WCommandLine and SysErrorMessage.

Looking at Windows codes, 740 is

ERROR_ELEVATION_REQUIRED
740 (0x2E4)
The requested operation requires elevation.

( System Error Codes (500-999) (WinError.h) - Win32 apps | Microsoft Learn ). It seems we didn’t have permissions to execute Lazarus. So this matches your finding. So error message was right, albeit cryptic.

I would recommend that, instead of “elevating” the CGE editor privileges, you fix the Lazarus privileges. For some reason, your Lazarus can be executed only by administrator, at least the WinAPI used by TProcess behaves like it. For security, it’s better to not run “normal” applications with admin privileges.