I work with many projects.

Is there a command-line parameter to start PL/SQL Developer and open a specific project?

Hmmm... I tried double clicking the .prj file in Explorer, but it get a little awckward when you already have some open files.

No, this is not possible. The only possibility is the "Auto Save Desktop" preference, which will automatically reopen the last project.

I have to work with many projects simultaneously: dev, test, prod.

I created projects:
dev, test, prod.

Then I created shortcuts: ...\PlSqlDev.exe Desktop=dev, ...\PlSqlDev.exe Desktop=test, ...\PlSqlDev.exe Desktop=prod.

I started shortcut dev and opened project dev and so on. Then I closed all three programs.

And now i am fighting with two problems:
1. If I start one of the shortcuts an error-window appears: Cannot open file "d:\temp\PLS-Recovery\133232.001".

2. I start shortcut dev, then test and then prod. I have now 3 PlSqlDev running. I close the third (prod) window. Now are 2 PlSqlDev running. I double-click at windows explorer on a xxx.sql file. I would like to open this file in second (test) Window, but a third PlSqlDev (prod) starts and opens my xxx.sql.

Suggestions:
a. Open a projects with command line parameter.
b. Associate a project with one's own Desktop (Project options)

I have added this to the list of enhancement requests.

What about the error: "Cannot open file "d:\temp\PLS-Recovery\133232.001" after start?

Sorry, I missed that. Did this file exist and was it accessible (e.g. not locked by some other process)?

No, this file doesn't exist.

In D:\Temp\PLS-Recovery\desktop.dev.cfg file i have found following:

It seems that the config file and the actually file system are inconsistent. We'll check it out.

You probably need to delete the desktop.dev.cfg file to get rid of the error message.

Add my vote for the ability to open a specific project from the command line. I have multiple environments that I am testing at once, and I'd like to be able to have the ability to automatically open a specific project from a shortcut, *and* be able to have multiple PL/SQL applications open, each using a different project.