Pour vider la PRAM c'est 2, et deux seulement, redémarrages en maintenant les touches Commande-Option-P-R au redémarrage (c'est écrit dans l'Aide Mac ! et sur le site apple). Si vos faites cette opération en redémarrant à froid (c'est-à-dire en allumant l'ordinateur, pas en le mettant au réfrigérateur !) vous videz aussi la NVRAM (et pas svram)
L'article d'Apple :
Resetting PRAM and NVRAM on iMac, iBook, and Power Mac computers
1. Shut down the computer.
2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Press the power button to turn the computer on. You will hear the computer's startup sound.
4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys.
Your computer's PRAM and the NVRAM are reset to the default values. The clock settings were not changed. See
Resetting PRAM on PowerBook computers
To reset the PRAM in your PowerBook computer, follow the steps in technical document 14449: "PowerBook: Resetting Power Manager."
Resetting PRAM on Earlier computers
Follow these steps for Power Macintosh computers with NuBus expansion slots, and Macintosh computers with a 68000-family microprocessor and System 7 or later.
1. Shut down the computer.
2. Locate the following keys on your keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
3. Turn on the computer.
4. Press and hold the Command-Option-P-R keys. You must press this key combination before the Welcome to Macintosh screen appears.
5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.
6. Release the keys.
The parameter RAM in your Macintosh is reset to the default values. The clock setting are not changed.
Contents of PRAM
Contents of PRAM are as follows. Some Macintosh computers may not have all the settings described below.
* Status of AppleTalk
* Serial Port Configuration and Port definition
* Alarm clock setting
* Application font
* Serial printer location
* Autokey rate
* Autokey dela
* Speaker volume
* Attention (beep) sound
* Double-click time
* Caret blink time (insertion point rate)
* Mouse scaling (mouse speed)
* Startup disk
* Menu blink count
* Monitor Depth
* 32 Bit addressing
* Virtual Memory
* Ram Disk
* Disk Cache
Salutations;
