This usually means the manage-bde command was typed with a switch or drive letter it did not expect. Using the correct syntax fixes it. Jump to your situation below or work through the methods in order.
The manage-bde message the parameter is incorrect almost always means a syntax mistake: a mistyped switch, a missing or wrong drive letter, or options combined in a way manage-bde does not accept. manage-bde is strict about its switches, so manage-bde -status C: works while a typo or an unsupported combination is rejected. The fix is to check the exact syntax, run manage-bde -? to list valid switches, and use the right drive letter with a colon. Occasionally the same message appears when the target drive letter does not exist or the drive is in a state manage-bde cannot read, so confirm the drive letter is correct. Getting the command right resolves it in nearly every case.
manage-bde parses each switch and argument exactly. If it meets something it does not recognise, a misspelled switch, a drive letter without a colon, or two options that cannot be used together, it cannot interpret the command and returns the parameter is incorrect.
So this is a command-line problem, not a BitLocker fault. Matching the documented syntax, using a valid drive letter, and listing the available switches with manage-bde -? gets the command into a form manage-bde understands.
“The parameter is incorrect is manage-bde being picky about how you typed the command. Usually it is a tiny thing, a switch spelled slightly wrong, or the drive letter written as C instead of C:. So I slow down and run manage-bde -? to see the exact switches, then type it cleanly, like manage-bde -status C:. Get the syntax right and it just works. It is almost never BitLocker itself, it is the command.”
manage-bde -status C:
C:.manage-bde -?
manage-bde -status -?.The parameter is incorrect is a syntax problem, so check the command carefully: spell switches correctly, include the drive letter with a colon like C:, and avoid unsupported option combinations. Run manage-bde -? to confirm the valid switches, then retype the command cleanly.
If the syntax is correct and the drive letter valid but it still fails, the target volume may be in a state manage-bde cannot read; try manage-bde -status with no drive letter to list all volumes and see which one is the problem. You can also submit your error to us for a tailored fix.